Remove useless u flags in regular expressions (#18509)

2025-12-21 23:44:08 +08:00
1 parent 97f2e81d06
commit c9eb4bcd9e
@@ -13,12 +13,11 @@ for (const size of [1, 1e1, 1e2]) {
    },
    {
      loop: () => trimIndentation(text).text,
-      "RegExp (inline)": () => text.replace(/[ \t]*$/u, ""),
+      "RegExp (inline)": () => text.replace(/[ \t]*$/, ""),
      "RegExp (stored)": (
        (regexp) => () =>
          text.replace(regexp, "")
-      )(/[ \t]*$/gu),
-      "RegExp (no `u` flag)": () => text.replace(/[ \t]*$/, ""),
+      )(/[ \t]*$/g),
    },
  );
 }
@@ -140,6 +140,12 @@ const configs = [
          exceptRange: true,
        },
      ],
+      "no-restricted-syntax": [
+        "error",
+        // Forbid `u` flag in regexp, kept for refactoring
+        // "Literal[regex.flags=/u/]",
+        // 'NewExpression[callee.name="RegExp"] > Literal.arguments:nth-child(2)[value=/u/]',
+      ],

      // Internal rules
      "prettier-internal-rules/jsx-identifier-case": "error",
@@ -49,7 +49,7 @@ function getEsbuildOptions({ packageConfig, file, cliOptions, buildOptions }) {
      process(text) {
        const exports = [
          ...text.matchAll(
-            /(?<=\n)exports\.(?<specifier>\w+) = \k<specifier>;/gu,
+            /(?<=\n)exports\.(?<specifier>\w+) = \k<specifier>;/g,
          ),
        ].map((match) => match.groups.specifier);

@@ -93,7 +93,7 @@ function getEsbuildOptions({ packageConfig, file, cliOptions, buildOptions }) {
    // #12493, not sure what the problem is, but replace the cjs version with esm version seems fix it
    {
      module: require.resolve("tslib"),
-      path: require.resolve("tslib").replace(/tslib\.js$/u, "tslib.es6.js"),
+      path: require.resolve("tslib").replace(/tslib\.js$/, "tslib.es6.js"),
    },
    // https://github.com/evanw/esbuild/issues/2103
    {
@@ -61,7 +61,7 @@ async function inlineWasmBinary(directory) {
  `;

  text = text.replaceAll(
-    /new URL\((?<url>".*?"), import\.meta\.url\)/gu,
+    /new URL\((?<url>".*?"), import\.meta\.url\)/g,
    "{/* $<url> */}",
  );

@@ -17,7 +17,7 @@ function esmifyTypescriptEslint(text) {
  */
  text = text.replaceAll(
    // TODO: Use duplicate capture group name when eslint supports
-    /(?<=\n)(?:const|let|var) (?<variable>\w+) = (?:__importStar\(require\(["'](?<moduleName1>.*?)["']\)\)|require\(["'](?<moduleName2>.*?)["']\));/gu,
+    /(?<=\n)(?:const|let|var) (?<variable>\w+) = (?:__importStar\(require\(["'](?<moduleName1>.*?)["']\)\)|require\(["'](?<moduleName2>.*?)["']\));/g,
    (...args) => {
      const groups = args.at(-1);
      return `import * as ${groups.variable} from "${groups.moduleName1 || groups.moduleName2}";`;
@@ -35,7 +35,7 @@ function esmifyTypescriptEslint(text) {
  ````
  */
  text = text.replaceAll(
-    /(?<=\n)(?:const|let|var) (?<variable>\w+) = __importDefault\(require\(["'](?<moduleName>.*?)["']\)\);/gu,
+    /(?<=\n)(?:const|let|var) (?<variable>\w+) = __importDefault\(require\(["'](?<moduleName>.*?)["']\)\);/g,
    outdent`
      import $<variable>_default_export from "$<moduleName>";
      const $<variable> = {default: $<variable>_default_export};
@@ -57,9 +57,9 @@ function esmifyTypescriptEslint(text) {
      "",
    );

-  text = text.replaceAll(/(?<=\n)(?:exports\.\w+ = )+void 0;/gu, "");
+  text = text.replaceAll(/(?<=\n)(?:exports\.\w+ = )+void 0;/g, "");
  text = text.replaceAll(
-    /(?<=\n)exports\.(?<specifier>\w+) = (?<variable>\w+);/gu,
+    /(?<=\n)exports\.(?<specifier>\w+) = (?<variable>\w+);/g,
    (...args) => {
      const { variable, specifier } = args.at(-1);
      if (specifier === variable) {
@@ -71,7 +71,7 @@ function esmifyTypescriptEslint(text) {
  );

  text = text.replaceAll(
-    /(?<=\n)exports\.(?<specifier>\w+)(?= = `)/gu,
+    /(?<=\n)exports\.(?<specifier>\w+)(?= = `)/g,
    "export const $<specifier>",
  );

@@ -85,7 +85,7 @@ function esmifyTypescriptEslint(text) {
  ````
  */
  text = text.replaceAll(
-    /(?<=\n)__exportStar\(require\(["'](?<moduleName>.*?)["']\), exports\);/gu,
+    /(?<=\n)__exportStar\(require\(["'](?<moduleName>.*?)["']\), exports\);/g,
    'export * from "$<moduleName>";',
  );

@@ -99,7 +99,7 @@ function esmifyTypescriptEslint(text) {
  ````
  */
  text = text.replaceAll(
-    /(?<=\n)Object\.defineProperty\(exports, "(?<specifier>\w+)", \{ enumerable: true, get: function \(\) \{ return (?<value>.*?); \} \}\);/gu,
+    /(?<=\n)Object\.defineProperty\(exports, "(?<specifier>\w+)", \{ enumerable: true, get: function \(\) \{ return (?<value>.*?); \} \}\);/g,
    "export const $<specifier> = $<value>;",
  );

@@ -114,7 +114,7 @@ function esmifyTypescriptEslint(text) {
  ````
  */
  text = text.replaceAll(
-    /(?<=\n)exports\.(?<specifier>\w+) = __importStar\(require\(["'](?<moduleName>.*?)["']\)\);/gu,
+    /(?<=\n)exports\.(?<specifier>\w+) = __importStar\(require\(["'](?<moduleName>.*?)["']\)\);/g,
    outdent`
      import * as $<specifier>_namespace_export from "$<moduleName>";
      export {$<specifier>_namespace_export as $<specifier>};
@@ -136,7 +136,7 @@ function esmifyTypescriptEslint(text) {
  ```
   */
  text = text.replaceAll(
-    /(?<=\n\}\))\((?<name>\S+) \|\| \(exports\.\k<name> = \k<name> = \{\}\)\);/gu,
+    /(?<=\n\}\))\((?<name>\S+) \|\| \(exports\.\k<name> = \k<name> = \{\}\)\);/g,
    outdent`
      ($<name> ??= {});
      export {$<name>};
@@ -6,7 +6,7 @@ import { PROJECT_ROOT, writeFile } from "../../utilities/index.js";
 import UNUSED_SPECIFIERS from "./typescript-unused-specifiers.js";

 function* getModules(text) {
-  const parts = text.split(/(?<=\n)(\/\/ src\/\S+\n)/u);
+  const parts = text.split(/(?<=\n)(\/\/ src\/\S+\n)/);

  let start = parts[0].length;

@@ -73,7 +73,7 @@ class TypeScriptModuleSource {
        escapeStringRegexp(end),
        "(?=\n)",
      ].join(""),
-      "gsu",
+      "gs",
    );

    this.#source.replaceAll(regexp, replacement);
@@ -150,7 +150,7 @@ function getExports(entry) {
  const exports = lines
    .map((line) => {
      const match = line.match(
-        /^\s*(?<specifier>.*?): \(\) => (?<variable>.*?),?$/u,
+        /^\s*(?<specifier>.*?): \(\) => (?<variable>.*?),?$/,
      );

      if (!match) {
@@ -26,11 +26,11 @@ function generatePackageJson(packageJson, { packageConfig }) {
            return [
              isPlugin ? `./plugins/${basename}` : `./${basename}`,
              {
-                types: `./${file.output.replace(/\.js$/u, ".d.ts")}`,
+                types: `./${file.output.replace(/\.js$/, ".d.ts")}`,
                // `module-sync` condition can prevent CJS plugins from working: https://github.com/prettier/prettier/issues/17139
                // Perform a test before re-adding it.
                require: `./${file.output}`,
-                default: `./${file.output.replace(/\.js$/u, ".mjs")}`,
+                default: `./${file.output.replace(/\.js$/, ".mjs")}`,
              },
            ];
          }),
@@ -56,7 +56,7 @@ function generatePackageJson(packageJson, { packageConfig }) {
              [`./parser-${basename}.js`, `./${file.output}`],
              [
                `./esm/parser-${basename}.mjs`,
-                `./${file.output.replace(/\.js$/u, ".mjs")}`,
+                `./${file.output.replace(/\.js$/, ".mjs")}`,
              ],
            ];
          }),
@@ -99,17 +99,17 @@ const mainModule = {
            );

            text = text.replaceAll(
-              /(?<=\n)let tokenize;\n\{\n.*?\n\}(?=\n)/gsu,
+              /(?<=\n)let tokenize;\n\{\n.*?\n\}(?=\n)/gs,
              "",
            );

            text = text.replaceAll(
-              /(?<=\n)function highlight\(text\) \{\n.*?\n\}(?=\n)/gsu,
+              /(?<=\n)function highlight\(text\) \{\n.*?\n\}(?=\n)/gs,
              "function highlight(text) {return text}",
            );

            text = text.replaceAll(
-              /(?<=\n)function getDefs\(enabled\) \{\n.*?\n\}(?=\n)/gsu,
+              /(?<=\n)function getDefs\(enabled\) \{\n.*?\n\}(?=\n)/gs,
              outdent`
                function getDefs() {
                  return new Proxy({}, {get: () => (text) => text})
@@ -269,7 +269,7 @@ const pluginFiles = [
        module: require.resolve("@babel/parser"),
        process: (text) =>
          text.replaceAll(
-            /const entity\s?=\s?entities\[desc\];/gu,
+            /const entity\s?=\s?entities\[desc\];/g,
            "const entity = undefined;",
          ),
      },
@@ -360,7 +360,7 @@ const pluginFiles = [
      {
        module: "*",
        process(text, file) {
-          if (/require\(["'](?:typescript|ts-api-utils)["']\)/u.test(text)) {
+          if (/require\(["'](?:typescript|ts-api-utils)["']\)/.test(text)) {
            throw new Error(`Unexpected \`require("typescript")\` in ${file}.`);
          }

@@ -476,7 +476,7 @@ const pluginFiles = [
        process(text) {
          const typescriptVariables = [
            ...text.matchAll(
-              /import (?<variable>\w+) from ["']typescript["']/gu,
+              /import (?<variable>\w+) from ["']typescript["']/g,
            ),
          ].map((match) => match.groups.variable);

@@ -484,13 +484,13 @@ const pluginFiles = [
          text = text.replaceAll(
            new RegExp(
              String.raw`".*?" in (?:${typescriptVariables.join("|")})(?=\W)`,
-              "gu",
+              "g",
            ),
            "true",
          );

          text = text.replaceAll(
-            /(?<=import )(?=\w+ from ["']typescript["'])/gu,
+            /(?<=import )(?=\w+ from ["']typescript["'])/g,
            "* as ",
          );

@@ -601,10 +601,10 @@ const pluginFiles = [
          );
          text = text.replace("const _visitor = new _Visitor$2()", "");
          text = text.replaceAll(
-            /const (.*?) = new BuiltinType\(BuiltinTypeName\..*?\);/gu,
+            /const (.*?) = new BuiltinType\(BuiltinTypeName\..*?\);/g,
            "const $1 = undefined;",
          );
-          text = text.replaceAll(/var output_ast =.*?;\n/gsu, "var output_ast");
+          text = text.replaceAll(/var output_ast =.*?;\n/gs, "var output_ast");

          text = text.replace(
            "const serializer = new IcuSerializerVisitor();",
@@ -616,62 +616,62 @@ const pluginFiles = [
          );

          text = text.replaceAll(
-            /function transformExpressionsInExpression\(.*?\n.*?\n\}\n/gsu,
+            /function transformExpressionsInExpression\(.*?\n.*?\n\}\n/gs,
            "function transformExpressionsInExpression(){}",
          );

          text = text.replaceAll(
-            /const deferTriggerToR3TriggerInstructionsMap = new Map\(\[\n.*?\n\]\);\n/gsu,
+            /const deferTriggerToR3TriggerInstructionsMap = new Map\(\[\n.*?\n\]\);\n/gs,
            "const deferTriggerToR3TriggerInstructionsMap = undefined;",
          );

          text = text.replaceAll(
-            /const BINARY_OPERATORS = new Map\(\[\n.*?\n\]\);\n/gsu,
+            /const BINARY_OPERATORS = new Map\(\[\n.*?\n\]\);\n/gs,
            "const BINARY_OPERATORS = undefined;",
          );

          text = text.replaceAll(
-            /const PIPE_BINDINGS = \[\n.*?\n\];\n/gsu,
+            /const PIPE_BINDINGS = \[\n.*?\n\];\n/gs,
            "const PIPE_BINDINGS = undefined;",
          );

          text = text.replaceAll(
-            /const TEXT_INTERPOLATE_CONFIG = \{\n.*?\n\};\n/gsu,
+            /const TEXT_INTERPOLATE_CONFIG = \{\n.*?\n\};\n/gs,
            "const TEXT_INTERPOLATE_CONFIG = undefined;",
          );

          text = text.replaceAll(
-            /const CHAINABLE = new Set\(\[\n.*?\n\]\);\n/gsu,
+            /const CHAINABLE = new Set\(\[\n.*?\n\]\);\n/gs,
            "const CHAINABLE = undefined;",
          );

          text = text.replaceAll(
-            /const PROPERTY_INTERPOLATE_CONFIG = \{\n.*?\n\};\n/gsu,
+            /const PROPERTY_INTERPOLATE_CONFIG = \{\n.*?\n\};\n/gs,
            "const PROPERTY_INTERPOLATE_CONFIG = undefined;",
          );
          text = text.replaceAll(
-            /const STYLE_PROP_INTERPOLATE_CONFIG = \{\n.*?\n\};\n/gsu,
+            /const STYLE_PROP_INTERPOLATE_CONFIG = \{\n.*?\n\};\n/gs,
            "const STYLE_PROP_INTERPOLATE_CONFIG = undefined;",
          );

          text = text.replaceAll(
-            /const ATTRIBUTE_INTERPOLATE_CONFIG = \{\n.*?\n\};\n/gsu,
+            /const ATTRIBUTE_INTERPOLATE_CONFIG = \{\n.*?\n\};\n/gs,
            "const ATTRIBUTE_INTERPOLATE_CONFIG = undefined;",
          );
          text = text.replaceAll(
-            /const STYLE_MAP_INTERPOLATE_CONFIG = \{\n.*?\n\};\n/gsu,
+            /const STYLE_MAP_INTERPOLATE_CONFIG = \{\n.*?\n\};\n/gs,
            "const STYLE_MAP_INTERPOLATE_CONFIG = undefined;",
          );
          text = text.replaceAll(
-            /const CLASS_MAP_INTERPOLATE_CONFIG = \{\n.*?\n\};\n/gsu,
+            /const CLASS_MAP_INTERPOLATE_CONFIG = \{\n.*?\n\};\n/gs,
            "const CLASS_MAP_INTERPOLATE_CONFIG = undefined;",
          );
          text = text.replaceAll(
-            /const PURE_FUNCTION_CONFIG = \{\n.*?\n\};\n/gsu,
+            /const PURE_FUNCTION_CONFIG = \{\n.*?\n\};\n/gs,
            "const PURE_FUNCTION_CONFIG = undefined;",
          );
          text = text.replaceAll(
-            /const NAMED_ENTITIES = \{\n.*?\n\};\n/gsu,
+            /const NAMED_ENTITIES = \{\n.*?\n\};\n/gs,
            "const NAMED_ENTITIES = {};",
          );

@@ -749,15 +749,15 @@ const pluginFiles = [
          );

          // This passed to plugins, our plugin don't need access to the options
-          text = text.replace(/(?<=\sconst syntax = )\{.*?\n\}(?=;\n)/su, "{}");
+          text = text.replace(/(?<=\sconst syntax = )\{.*?\n\}(?=;\n)/s, "{}");

          text = text.replaceAll(
-            /\sclass \S+ extends[(\s]+node\(.*?\).*?\{(?:\n.*?\n)?\}\n/gsu,
+            /\sclass \S+ extends[(\s]+node\(.*?\).*?\{(?:\n.*?\n)?\}\n/gs,
            "\n",
          );

          text = text.replaceAll(
-            /\nvar api\S* = \s*(?:\/\*#__PURE__\*\/)?\s*Object\.freeze\(\{.*?\n\}\);/gsu,
+            /\nvar api\S* = \s*(?:\/\*#__PURE__\*\/)?\s*Object\.freeze\(\{.*?\n\}\);/gs,
            "",
          );

@@ -777,7 +777,7 @@ const pluginFiles = [
          );

          text = text.replace(
-            /(?<=\n)export .*?;/u,
+            /(?<=\n)export .*?;/,
            "export { preprocess, getVoidTags, visitorKeys };",
          );

@@ -801,7 +801,7 @@ function createPluginModule(file) {

  const { input, ...buildOptions } = file;
  const { pluginName } = input.match(
-    /\/plugins\/(?<pluginName>.*?)\.js$/u,
+    /\/plugins\/(?<pluginName>.*?)\.js$/,
  ).groups;

  const umdVariableName = `prettierPlugins.${pluginName}`;
@@ -66,7 +66,7 @@ function transformMethodCallToFunctionCall(node, functionName) {
 function createMethodCallTransform({ methodName, argumentsLength }) {
  const functionName = `__${methodName}`;
  const fileName = `method-${methodName.replaceAll(
-    /[A-Z]/gu,
+    /[A-Z]/g,
    (character) => `-${character.toLowerCase()}`,
  )}.js`;
  const functionImplementationUrl = new URL(
@@ -34,7 +34,7 @@ const nextVersion = `${semver.major(version)}.${semver.minor(
 const postGlob = path.join(blogDir, `????-??-??-${nextVersion}.md`);
 const postFile = path.join(
  blogDir,
-  `${new Date().toISOString().replace(/T.+/u, "")}-${nextVersion}.md`,
+  `${new Date().toISOString().replace(/T.+/, "")}-${nextVersion}.md`,
 );

 const categoriesByDir = new Map(
@@ -66,20 +66,20 @@ function toDts(text) {
  text = text.replaceAll("'use strict';", "  ");

  // `{+foo: string}` -> `{foo: string}`
-  text = text.replaceAll(/(?<=\n)(?<indention>[ {2}]+)\+/gu, "$<indention>");
+  text = text.replaceAll(/(?<=\n)(?<indention>[ {2}]+)\+/g, "$<indention>");

  // `{foo: interface {}}` -> `{foo: {}}`
  text = text.replaceAll(": interface {", ": {");

  // `{foo: interface extends T {}}` -> `{foo: T & {}}`
  text = text.replaceAll(
-    /(?<=: )interface extends (?<type>\w+)(?= \{)/gu,
+    /(?<=: )interface extends (?<type>\w+)(?= \{)/g,
    "$<type> & ",
  );

  // `$ReadOnlyArray<?T>` -> `ReadonlyArray<T | null>`
  text = text.replaceAll(
-    /\$ReadOnlyArray<\?(\w+)>/gu,
+    /\$ReadOnlyArray<\?(\w+)>/g,
    "ReadonlyArray<$1 | null>",
  );

@@ -91,7 +91,7 @@ function toDts(text) {

  // `{[string]: T}` -> `{[key: string]: T}`
  text = text.replaceAll(
-    /(?<=\n)(?<indention>[ {2}]+)\[(?<type>string)\](?=: )/gu,
+    /(?<=\n)(?<indention>[ {2}]+)\[(?<type>string)\](?=: )/g,
    "$<indention>[key: $<type>]",
  );

@@ -19,7 +19,7 @@ async function getRemovedSpecifiers(code, exports) {
  const specifiers = [];
  for (const { text } of errors) {
    const match = text.match(
-      /^"(?<variable>.*?)" is not declared in this file$/u,
+      /^"(?<variable>.*?)" is not declared in this file$/,
    );

    if (match) {
@@ -39,14 +39,14 @@ for (const file of [
  }
 }

-const authorRegex = /by @[\w-]+|by \[@([\w-]+)\]\(https:\/\/github\.com\/\1\)/u;
-const titleRegex = /^#{4} (.*?)\((#\d{4,}|\[#\d{4,}\])/u;
+const authorRegex = /by @[\w-]+|by \[@([\w-]+)\]\(https:\/\/github\.com\/\1\)/;
+const titleRegex = /^#{4} (.*?)\((#\d{4,}|\[#\d{4,}\])/;

 const template = fs.readFileSync(
  new URL(TEMPLATE_FILE, CHANGELOG_ROOT),
  "utf8",
 );
-const templateComments = template.match(/<!--.*?-->/gsu);
+const templateComments = template.match(/<!--.*?-->/gs);
 const [templateAuthorLink] = template.match(authorRegex);
 const checkedFiles = new Map();

@@ -63,7 +63,7 @@ for (const category of CHANGELOG_CATEGORIES) {
      continue;
    }

-    const match = prFile.match(/^(\d{4,})(-\d+)?\.md$/u);
+    const match = prFile.match(/^(\d{4,})(-\d+)?\.md$/);
    const displayPath = `${CHANGELOG_DIR}/${category}/${prFile}`;

    if (!match) {
@@ -137,7 +137,7 @@ for (const category of CHANGELOG_CATEGORIES) {
      );
    }

-    if (/prettier master/iu.test(content)) {
+    if (/prettier master/i.test(content)) {
      showErrorMessage(
        `[${displayPath}]: Please use "main" instead of "master".`,
      );
@@ -9,7 +9,7 @@ import esbuild from "esbuild";

 export async function getSource(url, context, defaultGetSource) {
  if (
-    !/node_modules\/@babel\/(?:code-frame|highlight)/u.test(url) ||
+    !/node_modules\/@babel\/(?:code-frame|highlight)/.test(url) ||
    context.format !== "module"
  ) {
    return defaultGetSource(url, context, defaultGetSource);
@@ -13,7 +13,7 @@ const jsFiles = packageBuildConfigs
  .flatMap((packageConfig) =>
    packageConfig.modules.flatMap((module) =>
      module.files
-        .filter((file) => /\.[cm]?js$/u.test(file.output))
+        .filter((file) => /\.[cm]?js$/.test(file.output))
        .map((file) => path.join(packageConfig.distDirectory, file.output)),
    ),
  )
@@ -7,7 +7,7 @@ async function getNpmDependentsCount() {
    fetchText("https://www.npmjs.com/package/prettier"),
  );
  const dependentsCountNpm = Number(
-    npmPage.match(/"dependentsCount":"(?<dependentsCount>\d+)",/u).groups
+    npmPage.match(/"dependentsCount":"(?<dependentsCount>\d+)",/).groups
      .dependentsCount,
  );
  if (Number.isNaN(dependentsCountNpm)) {
@@ -28,7 +28,7 @@ async function getGithubDependentsCount() {
    githubPage
      .replaceAll("\n", "")
      .match(
-        /<svg.*?octicon-code-square.*?>.*?<\/svg>\s*(?<dependentsCount>[\d,]+)\s*Repositories\s*<\/a>/u,
+        /<svg.*?octicon-code-square.*?>.*?<\/svg>\s*(?<dependentsCount>[\d,]+)\s*Repositories\s*<\/a>/,
      )
      .groups.dependentsCount.replaceAll(",", ""),
  );
@@ -54,14 +54,14 @@ async function update({ repo }) {
    processFile("website/src/pages/index.jsx", (content) => {
      if (dependentsCountNpm) {
        content = content.replace(
-          /(<strong data-placeholder="dependent-npm">)(.*?)(<\/strong>)/u,
+          /(<strong data-placeholder="dependent-npm">)(.*?)(<\/strong>)/,
          `$1${formatNumber(dependentsCountNpm)}$3`,
        );
      }

      if (dependentsCountGithub) {
        content = content.replace(
-          /(<strong data-placeholder="dependent-github">)(.*?)(<\/strong>)/u,
+          /(<strong data-placeholder="dependent-github">)(.*?)(<\/strong>)/,
          `$1${formatNumber(dependentsCountGithub)}$3`,
        );
      }
@@ -12,16 +12,14 @@ export default async function updateVersion({ version, next }) {

  // Update github issue templates
  processFile(".github/ISSUE_TEMPLATE/formatting.md", (content) =>
-    content.replace(/^(\*\*Prettier ).*?(\*\*)$/mu, `$1${version}$2`),
+    content.replace(/^(\*\*Prettier ).*?(\*\*)$/m, `$1${version}$2`),
  );
  processFile(".github/ISSUE_TEMPLATE/integration.md", (content) =>
-    content.replace(/^(- Prettier Version: ).*$/mu, `$1${version}`),
+    content.replace(/^(- Prettier Version: ).*$/m, `$1${version}`),
  );

  await runYarn(["install"], { cwd: "./website" });

  process.env.PRETTIER_VERSION = version;
-  await runYarn(["update-stable-docs"], {
-    cwd: "./website",
-  });
+  await runYarn(["update-stable-docs"], { cwd: "./website" });
 }
@@ -50,7 +50,7 @@ for (const packageConfig of packageBuildConfigs) {
  /* `require` in `parser-typescript.js`, #12338 */
  for (const module of modules) {
    for (const file of module.files) {
-      if (!/\.m?js$/u.test(file.output) || excludedFiles.has(file.output)) {
+      if (!/\.m?js$/.test(file.output) || excludedFiles.has(file.output)) {
        continue;
      }
      console.log(`${file.output}: `);
@@ -48,7 +48,7 @@ export function getEntries(dirPath, options) {
    const filePath = path.join(dirPath, fileName);
    let [title, ...rest] = fs.readFileSync(filePath, "utf8").trim().split("\n");

-    const improvement = title.match(/\[IMPROVEMENT(:(\d+))?\]/u);
+    const improvement = title.match(/\[IMPROVEMENT(:(\d+))?\]/);

    const section = title.includes("[HIGHLIGHT]")
      ? "highlight"
@@ -100,11 +100,11 @@ export function replaceVersions(data, prevVer, newVer, isPatch = false) {

  return data
    .replaceAll(
-      /prettier stable/giu,
+      /prettier stable/gi,
      `Prettier ${isPatch ? prevVer : formatVersion(prevVer)}`,
    )
    .replaceAll(
-      /prettier main/giu,
+      /prettier main/gi,
      `Prettier ${isPatch ? newVer : formatVersion(newVer)}`,
    );
 }
@@ -115,12 +115,12 @@ function formatVersion(version) {

 function processTitle(title) {
  return title
-    .replaceAll(/\[(BREAKING|HIGHLIGHT|IMPROVEMENT(:\d+)?)\]/gu, "")
-    .replaceAll(/\s+/gu, " ")
-    .replace(/^#{4} [a-z]/u, (s) => s.toUpperCase())
-    .replaceAll(/(?<![[`])@([\w-]+)/gu, "[@$1](https://github.com/$1)")
+    .replaceAll(/\[(BREAKING|HIGHLIGHT|IMPROVEMENT(:\d+)?)\]/g, "")
+    .replaceAll(/\s+/g, " ")
+    .replace(/^#{4} [a-z]/, (s) => s.toUpperCase())
+    .replaceAll(/(?<![[`])@([\w-]+)/g, "[@$1](https://github.com/$1)")
    .replaceAll(
-      /(?<![[`])#(\d{4,})/gu,
+      /(?<![[`])#(\d{4,})/g,
      "[#$1](https://github.com/prettier/prettier/pull/$1)",
    );
 }
@@ -75,7 +75,7 @@ class Context {

    /* c8 ignore start */
    const { PRETTIER_PERF_REPEAT } = process.env;
-    if (PRETTIER_PERF_REPEAT && /^\d+$/u.test(PRETTIER_PERF_REPEAT)) {
+    if (PRETTIER_PERF_REPEAT && /^\d+$/.test(PRETTIER_PERF_REPEAT)) {
      return {
        name: "PRETTIER_PERF_REPEAT (environment variable)",
        debugRepeat: Number(PRETTIER_PERF_REPEAT),
@@ -48,7 +48,7 @@ function handleError(context, filename, error, printedFilename, ignoreUnknown) {
  }

  const isParseError = Boolean(error?.loc);
-  const isValidationError = /^Invalid \S+ value\./u.test(error?.message);
+  const isValidationError = /^Invalid \S+ value\./.test(error?.message);

  if (isParseError) {
    // `invalid.js: SyntaxError: Unexpected token (1:1)`.
@@ -43,7 +43,7 @@ function createLogger(logLevel = "log") {
        ...options,
      };
      message =
-        message.replaceAll(/^/gmu, prefix) + (options.newline ? "\n" : "");
+        message.replaceAll(/^/gm, prefix) + (options.newline ? "\n" : "");
      stream.write(message);

      if (options.clearable) {
@@ -8,7 +8,7 @@ const CHOICE_USAGE_MARGIN = 3;
 const CHOICE_USAGE_INDENTATION = 2;

 function indent(str, spaces) {
-  return str.replaceAll(/^/gmu, " ".repeat(spaces));
+  return str.replaceAll(/^/gm, " ".repeat(spaces));
 }

 function createDefaultValueDisplay(value) {
@@ -40,9 +40,9 @@ function convertEndOfLineOptionToCharacter(endOfLineOption) {
 }

 const regexps = new Map([
-  [CHARACTER_LF, /\n/gu],
-  [CHARACTER_CR, /\r/gu],
-  [CHARACTER_CRLF, /\r\n/gu],
+  [CHARACTER_LF, /\n/g],
+  [CHARACTER_CR, /\r/g],
+  [CHARACTER_CRLF, /\r\n/g],
 ]);
 /**
@param {string} text
@@ -63,7 +63,7 @@ function countEndOfLineCharacters(text, endOfLineCharacter) {
  return text.match(regex)?.length ?? 0;
 }

-const END_OF_LINE_REGEXP = /\r\n?/gu;
+const END_OF_LINE_REGEXP = /\r\n?/g;
 /**
@param {string} text
@returns {string}
@@ -31,7 +31,7 @@ function clean(original, cloned, parent) {
      delete cloned.text;

      // standalone pragma
-      if (/^\*\s*@(?:format|prettier)\s*$/u.test(original.text)) {
+      if (/^\*\s*@(?:format|prettier)\s*$/.test(original.text)) {
        return null;
      }
    }
@@ -76,7 +76,7 @@ function clean(original, cloned, parent) {
  }

  if (original.type === "selector-combinator") {
-    cloned.value = cloned.value.replaceAll(/\s+/gu, " ");
+    cloned.value = cloned.value.replaceAll(/\s+/g, " ");
  }

  if (original.type === "media-feature") {
@@ -105,7 +105,7 @@ function clean(original, cloned, parent) {
    cloned.unit = original.unit.toLowerCase();
  }
  if (original.type === "value-unknown") {
-    cloned.value = cloned.value.replaceAll(/;$/gu, "");
+    cloned.value = cloned.value.replaceAll(/;$/g, "");
  }

  if (original.type === "selector-attribute") {
@@ -118,7 +118,7 @@ function clean(original, cloned, parent) {
    if (original.value) {
      let { value } = cloned;
      // Parser only understands the `i` flag
-      if (/\s[a-zA-Z]$/u.test(value)) {
+      if (/\s[a-z]$/i.test(value)) {
        // Add an extra property to make sure flag is preserved
        cloned.__prettier_attribute_selector_flag = value.at(-1);
        value = value.slice(0, -1);
@@ -127,7 +127,7 @@ function clean(original, cloned, parent) {
      value = value.trim();

      value = value.replace(
-        /^(?<quote>["'])(?<value>.*?)\k<quote>$/u,
+        /^(?<quote>["'])(?<value>.*?)\k<quote>$/,
        "$<value>",
      );

@@ -147,7 +147,7 @@ function clean(original, cloned, parent) {
    original.value
  ) {
    cloned.value = cloned.value.replaceAll(
-      /([\d+.e-]+)([a-z]*)/giu,
+      /([\d+.e-]+)([a-z]*)/gi,
      (match, numStr, unit) => {
        const num = Number(numStr);
        return Number.isNaN(num) ? match : num + unit.toLowerCase();
@@ -220,7 +220,7 @@ function clean(original, cloned, parent) {
 clean.ignoredProperties = ignoredProperties;

 function cleanCSSStrings(value) {
-  return value.replaceAll("'", '"').replaceAll(/\\([^\da-f])/giu, "$1");
+  return value.replaceAll("'", '"').replaceAll(/\\([^\da-f])/gi, "$1");
 }

 export default clean;
@@ -109,7 +109,7 @@ function getValueRootOffset(node) {

  if (node.type === "css-atrule" && typeof node.name === "string") {
    result +=
-      1 + node.name.length + node.raws.afterName.match(/^\s*:?\s*/u)[0].length;
+      1 + node.name.length + node.raws.afterName.match(/^\s*:?\s*/)[0].length;
  }

  if (node.type !== "css-atrule" && typeof node.raws?.between === "string") {
@@ -238,7 +238,7 @@ function replaceQuotesInInlineComments(text) {
  for (const [start, end] of inlineCommentsToReplace) {
    text =
      text.slice(0, start) +
-      text.slice(start, end).replaceAll(/["'*]/gu, " ") +
+      text.slice(start, end).replaceAll(/["'*]/g, " ") +
      text.slice(end);
  }

@@ -6,7 +6,7 @@ function parseSelector(selector) {
  // the content of the comment as selectors which turns it into complete
  // garbage. Better to print the whole selector as-is and not try to parse
  // and reformat it.
-  if (/\/[/*]/u.test(selector.replaceAll(/"[^"]+"|'[^']+'/gu, ""))) {
+  if (/\/[/*]/.test(selector.replaceAll(/"[^"]+"|'[^']+'/g, ""))) {
    return {
      type: "selector-unknown",
      value: selector.trim(),
@@ -192,7 +192,7 @@ function parseValue(value, options) {

  const parsedResult = parseNestedValue(result, options);

-  return addTypePrefix(parsedResult, "value-", /^selector-/u);
+  return addTypePrefix(parsedResult, "value-", /^selector-/);
 }

 export default parseValue;
@@ -19,8 +19,8 @@ import { hasIgnorePragma, hasPragma } from "./pragma.js";
 import isModuleRuleName from "./utilities/is-module-rule-name.js";
 import isSCSSNestedPropertyNode from "./utilities/is-scss-nested-property-node.js";

-const DEFAULT_SCSS_DIRECTIVE = /(\s*)(!default).*$/u;
-const GLOBAL_SCSS_DIRECTIVE = /(\s*)(!global).*$/u;
+const DEFAULT_SCSS_DIRECTIVE = /(\s*)(!default).*$/;
+const GLOBAL_SCSS_DIRECTIVE = /(\s*)(!global).*$/;

 function parseNestedCSS(node, options) {
  if (isObject(node)) {
@@ -232,7 +232,7 @@ function parseNestedCSS(node, options) {

      // only css support custom-selector
      if (options.parser === "css" && node.name === "custom-selector") {
-        const customSelector = node.params.match(/:--\S+\s+/u)[0].trim();
+        const customSelector = node.params.match(/:--\S+\s+/)[0].trim();
        node.customSelector = customSelector;
        node.selector = parseSelector(
          node.params.slice(customSelector.length).trim(),
@@ -307,7 +307,7 @@ function parseNestedCSS(node, options) {
      }

      if (name === "at-root") {
-        if (/^\(\s*(?:without|with)\s*:.+\)$/su.test(params)) {
+        if (/^\(\s*(?:without|with)\s*:.+\)$/s.test(params)) {
          node.params = parseValue(params, options);
        } else {
          node.selector = parseSelector(params);
@@ -344,11 +344,11 @@ function parseNestedCSS(node, options) {
      ) {
        // Remove unnecessary spaces in SCSS variable arguments
        // Move spaces after the `...`, so we can keep the range correct
-        params = params.replace(/(\$\S+?)(\s+)?\.{3}/u, "$1...$2");
+        params = params.replace(/(\$\S+?)(\s+)?\.{3}/, "$1...$2");
        // Remove unnecessary spaces before SCSS control, mixin and function directives
        // Move spaces after the `(`, so we can keep the range correct
        // Only match the first function call at the beginning, not nested ones
-        params = params.replace(/^(?!if)([^"'\s(]+)(\s+)\(/u, "$1($2");
+        params = params.replace(/^(?!if)([^"'\s(]+)(\s+)\(/, "$1($2");

        node.value = parseValue(params, options);
        delete node.params;
@@ -7,10 +7,10 @@ function printUnit(unit) {
  return CSS_UNITS.has(lowercased) ? CSS_UNITS.get(lowercased) : unit;
 }

-const STRING_REGEX = /(["'])(?:(?!\1)[^\\]|\\.)*\1/gsu;
-const NUMBER_REGEX = /(?:\d*\.\d+|\d+\.?)(?:e[+-]?\d+)?/giu;
-const STANDARD_UNIT_REGEX = /[a-z]+/giu;
-const WORD_PART_REGEX = /[$@]?[_a-z\u0080-\uFFFF][\w\u0080-\uFFFF-]*/giu;
+const STRING_REGEX = /(["'])(?:(?!\1)[^\\]|\\.)*\1/gs;
+const NUMBER_REGEX = /(?:\d*\.\d+|\d+\.?)(?:e[+-]?\d+)?/gi;
+const STANDARD_UNIT_REGEX = /[a-z]+/gi;
+const WORD_PART_REGEX = /[$@]?[_a-z\u0080-\uFFFF][\w\u0080-\uFFFF-]*/gi;
 const ADJUST_NUMBERS_REGEX = new RegExp(
  STRING_REGEX.source +
    "|" +
@@ -18,7 +18,7 @@ const ADJUST_NUMBERS_REGEX = new RegExp(
    `(${WORD_PART_REGEX.source})?` +
    `(${NUMBER_REGEX.source})` +
    `(${STANDARD_UNIT_REGEX.source})?`,
-  "giu",
+  "gi",
 );

 function adjustStrings(value, options) {
@@ -33,7 +33,7 @@ function quoteAttributeValue(value, options) {
  // To support future flags, we simply check if it's an alphabet letter
  // https://github.com/prettier/prettier/pull/17865#discussion_r2332698101
  let flag = "";
-  const match = value.match(/^(?<value>.+?)\s+(?<flag>[a-zA-Z])$/u);
+  const match = value.match(/^(?<value>.+?)\s+(?<flag>[a-z])$/i);
  if (match) {
    ({ value, flag } = match.groups);
  }
@@ -72,7 +72,7 @@ function printCssNumber(rawNumber) {
  return (
    printNumber(rawNumber)
      // Remove trailing `.0`.
-      .replace(/\.0(?=$|e)/u, "")
+      .replace(/\.0(?=$|e)/, "")
  );
 }

@@ -112,7 +112,7 @@ function genericPrint(path, options, print) {
      const isColon = trimmedBetween === ":";
      const hasSpaceAfterColon = rawBetween.endsWith(" ") && isColon;
      const isValueAllSpace =
-        typeof node.value === "string" && /^ *$/u.test(node.value);
+        typeof node.value === "string" && /^ *$/.test(node.value);
      let value = typeof node.value === "string" ? node.value : print("value");

      value = hasComposesNode(node) ? removeLines(value) : value;
@@ -126,7 +126,7 @@ function genericPrint(path, options, print) {
      }

      return [
-        node.raws.before.replaceAll(/[\s;]/gu, ""),
+        node.raws.before.replaceAll(/[\s;]/g, ""),
        // Less variable
        (parentNode.type === "css-atrule" && parentNode.variable) ||
        insideIcssRuleNode(path)
@@ -147,17 +147,17 @@ function genericPrint(path, options, print) {
          : "",
        value,
        node.raws.important
-          ? node.raws.important.replace(/\s*!\s*important/iu, " !important")
+          ? node.raws.important.replace(/\s*!\s*important/i, " !important")
          : node.important
            ? " !important"
            : "",
        node.raws.scssDefault
-          ? node.raws.scssDefault.replace(/\s*!default/iu, " !default")
+          ? node.raws.scssDefault.replace(/\s*!default/i, " !default")
          : node.scssDefault
            ? " !default"
            : "",
        node.raws.scssGlobal
-          ? node.raws.scssGlobal.replace(/\s*!global/iu, " !global")
+          ? node.raws.scssGlobal.replace(/\s*!global/i, " !global")
          : node.scssGlobal
            ? " !global"
            : "",
@@ -248,9 +248,9 @@ function genericPrint(path, options, print) {
                    ? ""
                    : node.name.endsWith(":")
                      ? " "
-                      : /^\s*\n\s*\n/u.test(node.raws.afterName)
+                      : /^\s*\n\s*\n/.test(node.raws.afterName)
                        ? [hardline, hardline]
-                        : /^\s*\n/u.test(node.raws.afterName)
+                        : /^\s*\n/.test(node.raws.afterName)
                          ? hardline
                          : " "
                  : " ",
@@ -323,7 +323,7 @@ function genericPrint(path, options, print) {

    case "media-feature":
      return maybeToLowerCase(
-        adjustStrings(node.value.replaceAll(/ +/gu, " "), options),
+        adjustStrings(node.value.replaceAll(/ +/g, " "), options),
      );

    case "media-colon":
@@ -337,9 +337,7 @@ function genericPrint(path, options, print) {

    case "media-url":
      return adjustStrings(
-        node.value
-          .replaceAll(/^url\(\s+/giu, "url(")
-          .replaceAll(/\s+\)$/gu, ")"),
+        node.value.replaceAll(/^url\(\s+/gi, "url(").replaceAll(/\s+\)$/g, ")"),
        options,
      );

@@ -123,8 +123,8 @@ function isDetachedRulesetDeclarationNode(node) {
  }

  return (
-    (typeof selector === "string" && /^@.+:.*$/u.test(selector)) ||
-    (selector.value && /^@.+:.*$/u.test(selector.value))
+    (typeof selector === "string" && /^@.+:.*$/.test(selector)) ||
+    (selector.value && /^@.+:.*$/.test(selector.value))
  );
 }

@@ -194,7 +194,7 @@ function isSCSSControlDirectiveNode(node, options) {
 }

 function isDetachedRulesetCallNode(node) {
-  return node.raws?.params && /^\(\s*\)$/u.test(node.raws.params);
+  return node.raws?.params && /^\(\s*\)$/.test(node.raws.params);
 }

 function isTemplatePlaceholderNode(node) {
@@ -356,7 +356,7 @@ function isColorAdjusterFuncNode(node) {
 }

 function lastLineHasInlineComment(text) {
-  return /\/\//u.test(text.split(/[\n\r]/u).pop());
+  return /\/\//.test(text.split(/[\n\r]/).pop());
 }

 function isAtWordPlaceholderNode(node) {
@@ -9,8 +9,8 @@ function isSCSSNestedPropertyNode(node, options) {
  }

  return node.selector
-    .replace(/\/\*.*?\*\//u, "")
-    .replace(/\/\/.*\n/u, "")
+    .replace(/\/\*.*?\*\//, "")
+    .replace(/\/\/.*\n/, "")
    .trim()
    .endsWith(":");
 }
@@ -109,7 +109,7 @@ function genericPrint(path, options, print) {
      return [
        '"',
        node.value
-          .replaceAll(/["\\]/gu, String.raw`\$&`)
+          .replaceAll(/["\\]/g, String.raw`\$&`)
          .replaceAll("\n", String.raw`\n`),
        '"',
      ];
@@ -26,7 +26,7 @@ function addBackslash(node) {
        childrenOrBody[i + 1].type === "MustacheStatement"
      ) {
        childrenOrBody[i].chars = childrenOrBody[i].chars.replace(
-          /\\$/u,
+          /\\$/,
          "\\\\",
        );
      }
@@ -126,8 +126,8 @@ function getErrorMessage(error) {
  */
  if (
    lines.length >= 4 &&
-    /^Parse error on line \d+:$/u.test(lines[0]) &&
-    /^-*\^$/u.test(lines.at(-2))
+    /^Parse error on line \d+:$/.test(lines[0]) &&
+    /^-*\^$/.test(lines.at(-2))
  ) {
    return lines.at(-1);
  }
@@ -147,8 +147,8 @@ function getErrorMessage(error) {
  */
  if (
    lines.length >= 4 &&
-    /:\s?$/u.test(lines[0]) &&
-    /^\(error occurred in '.*?' @ line \d+ : column \d+\)$/u.test(
+    /:\s?$/.test(lines[0]) &&
+    /^\(error occurred in '.*?' @ line \d+ : column \d+\)$/.test(
      lines.at(-1),
    ) &&
    lines[1] === "" &&
@@ -173,7 +173,7 @@ function print(path, options, print) {
        }

        if (parent.tag === "style") {
-          text = text.replaceAll(/^\n+/gu, "");
+          text = text.replaceAll(/^\n+/g, "");
          text = htmlWhitespace.trimEnd(text);
          text = htmlWhitespace.dedentString(text);

@@ -191,7 +191,7 @@ function print(path, options, print) {
      if (attrName) {
        // TODO: format style and srcset attributes
        if (attrName === "class") {
-          const formattedClasses = text.trim().split(/\s+/u).join(" ");
+          const formattedClasses = text.trim().split(/\s+/).join(" ");

          let leadingSpace = false;
          let trailingSpace = false;
@@ -199,13 +199,13 @@ function print(path, options, print) {
          if (path.parent.type === "ConcatStatement") {
            if (
              path.previous?.type === "MustacheStatement" &&
-              /^\s/u.test(text)
+              /^\s/.test(text)
            ) {
              leadingSpace = true;
            }
            if (
              path.next?.type === "MustacheStatement" &&
-              /\s$/u.test(text) &&
+              /\s$/.test(text) &&
              formattedClasses !== ""
            ) {
              trailingSpace = true;
@@ -695,14 +695,14 @@ function countNewLines(string) {
 function countLeadingNewLines(string) {
  /* c8 ignore next */
  string = typeof string === "string" ? string : "";
-  const newLines = (string.match(/^([^\S\n\r]*[\n\r])+/gu) || [])[0] || "";
+  const newLines = (string.match(/^([^\S\n\r]*[\n\r])+/g) || [])[0] || "";
  return countNewLines(newLines);
 }

 function countTrailingNewLines(string) {
  /* c8 ignore next */
  string = typeof string === "string" ? string : "";
-  const newLines = (string.match(/([\n\r][^\S\n\r]*)+$/gu) || [])[0] || "";
+  const newLines = (string.match(/([\n\r][^\S\n\r]*)+$/g) || [])[0] || "";
  return countNewLines(newLines);
 }

@@ -817,8 +817,8 @@ const isPathExpressionPartNeedBrackets = (part, index) => {

  return (
    (index !== 0 && PATH_EXPRESSION_FORBIDDEN_IN_FIRST_PART.has(part)) ||
-    /\s/u.test(part) ||
-    /^\d/u.test(part) ||
+    /\s/.test(part) ||
+    /^\d/.test(part) ||
    Array.prototype.some.call(part, (character) =>
      PATH_EXPRESSION_FORBIDDEN_CHARACTERS.has(character),
    )
@@ -31,7 +31,7 @@ function isVoidElement(node) {
 }

 function isWhitespaceNode(node) {
-  return node.type === "TextNode" && !/\S/u.test(node.chars);
+  return node.type === "TextNode" && !/\S/.test(node.chars);
 }

 function isPrettierIgnoreNode(node) {
@@ -64,12 +64,12 @@ function clean(original, cloned, parent) {
    ) {
      delete cloned.value;
    } else if (value) {
-      cloned.value = value.replaceAll(/'|&quot;|&apos;/gu, '"');
+      cloned.value = value.replaceAll(/'|&quot;|&apos;/g, '"');
    }
  }

  if (original.kind === "docType") {
-    cloned.value = original.value.toLowerCase().replaceAll(/\s+/gu, " ");
+    cloned.value = original.value.toLowerCase().replaceAll(/\s+/g, " ");
  }

  if (
@@ -5,7 +5,7 @@ function expandHeadingPseudoClassSelector(selector) {
    return ["h1", "h2", "h3", "h4", "h5", "h6"];
  }

-  const match = selector.match(/^:heading\((?<levels>\d+(?:,\s*\d+)*)\)$/u);
+  const match = selector.match(/^:heading\((?<levels>\d+(?:,\s*\d+)*)\)$/);
  if (!match) {
    return;
  }
@@ -28,7 +28,7 @@ const getCssStyleTags = (property) =>
      return selectors.flatMap((selector) => {
        const tagNames =
          expandHeadingPseudoClassSelector(selector) ??
-          (/^[\da-z]+$/iu.test(selector) ? [selector] : []);
+          (/^[\da-z]+$/i.test(selector) ? [selector] : []);

        return tagNames.map((tagName) => [tagName, style.value]);
      });
@@ -51,7 +51,7 @@ function embed(path, options) {

        return async (textToDoc, print) => {
          const content = getNodeContent(node, options);
-          let isEmpty = /^\s*$/u.test(content);
+          let isEmpty = /^\s*$/.test(content);
          let doc = "";
          if (!isEmpty) {
            doc = await textToDoc(htmlTrimPreserveIndentation(content), {
@@ -82,7 +82,7 @@ function embed(path, options) {
            const value =
              parser === "markdown"
                ? htmlWhitespace.dedentString(
-                    node.value.replace(/^[^\S\n]*\n/u, ""),
+                    node.value.replace(/^[^\S\n]*\n/, ""),
                  )
                : node.value;
            const textToDocOptions = { parser, __embeddedInHtml: true };
@@ -52,9 +52,9 @@ const printers = [
      const name = path.node.fullName;
      return (
        (name.startsWith("[") && name.endsWith("]")) ||
-        /^bind(?:on)?-/u.test(name) ||
+        /^bind(?:on)?-/.test(name) ||
        // Unofficial rudimentary support for some of the most used directives of AngularJS 1.x
-        /^ng-(?:if|show|hide|class|style)$/u.test(name)
+        /^ng-(?:if|show|hide|class|style)$/.test(name)
      );
    },
    print: createAngularPrinter("__ng_binding"),
@@ -71,7 +71,7 @@ const printers = [
    - `i18n="longDescription"`
    - `i18n-attr="longDescription"`
    */
-    test: (path /* , options */) => /^i18n(?:-.+)?$/u.test(path.node.fullName),
+    test: (path /* , options */) => /^i18n(?:-.+)?$/.test(path.node.fullName),
    print: printAngularI18n,
  },
  {
@@ -12,7 +12,7 @@ function printAngularControlFlowBlockParameters(
    node.sourceSpan.start.offset,
    node.sourceSpan.end.offset,
  );
-  const isEmpty = /^\s*$/u.test(content);
+  const isEmpty = /^\s*$/.test(content);

  if (isEmpty) {
    return "";
@@ -2,7 +2,7 @@ import { group, indent, line, replaceEndOfLine } from "../../document/index.js";
 import { getUnescapedAttributeValue } from "../utilities/index.js";
 import { formatAttributeValue } from "./utilities.js";

-const interpolationRegex = /\{\{(.+?)\}\}/su;
+const interpolationRegex = /\{\{(.+?)\}\}/s;

 const isAngularInterpolation = ({ node: { value } } /* , options*/) =>
  interpolationRegex.test(value);
@@ -12,6 +12,6 @@ const isClassNames = ({ node }, options) =>

 /** @type {AttributeValuePrint} */
 const printClassNames = (textToDoc, print, path /* , options*/) =>
-  getUnescapedAttributeValue(path.node).trim().split(/\s+/u).join(" ");
+  getUnescapedAttributeValue(path.node).trim().split(/\s+/).join(" ");

 export { isClassNames, printClassNames };
@@ -38,9 +38,9 @@ async function printVueVForDirective(textToDoc, print, path, options) {

 // modified from https://github.com/vuejs/vue/blob/v2.5.17/src/compiler/parser/index.js#L370-L387
 function parseVueVForDirective(value) {
-  const forAliasRE = /(.*?)\s+(in|of)\s+(.*)/su;
-  const forIteratorRE = /,([^,\]}]*)(?:,([^,\]}]*))?$/u;
-  const stripParensRE = /^\(|\)$/gu;
+  const forAliasRE = /(.*?)\s+(in|of)\s+(.*)/s;
+  const forIteratorRE = /,([^,\]}]*)(?:,([^,\]}]*))?$/;
+  const stripParensRE = /^\(|\)$/g;

  const inMatch = value.match(forAliasRE);
  if (!inMatch) {
@@ -10,17 +10,17 @@ const parseFunctions = [
  {
    // <!--[if ... ]> ... <![endif]-->
    regex:
-      /^(?<openingTagSuffix>\[if(?<condition>[^\]]*)\]>)(?<data>.*?)<!\s*\[endif\]$/su,
+      /^(?<openingTagSuffix>\[if(?<condition>[^\]]*)\]>)(?<data>.*?)<!\s*\[endif\]$/s,
    parse: parseIeConditionalStartEndComment,
  },
  {
    // <!--[if ... ]><!-->
-    regex: /^\[if(?<condition>[^\]]*)\]><!$/u,
+    regex: /^\[if(?<condition>[^\]]*)\]><!$/,
    parse: parseIeConditionalStartComment,
  },
  {
    // <!--<![endif]-->
-    regex: /^<!\s*\[endif\]$/u,
+    regex: /^<!\s*\[endif\]$/,
    parse: parseIeConditionalEndComment,
  },
 ];
@@ -64,7 +64,7 @@ function parseIeConditionalStartEndComment(node, match, parseHtml) {
    kind: "ieConditionalComment",
    complete,
    children,
-    condition: condition.trim().replaceAll(/\s+/gu, " "),
+    condition: condition.trim().replaceAll(/\s+/g, " "),
    sourceSpan: node.sourceSpan,
    startSourceSpan: new ParseSourceSpan(
      node.sourceSpan.start,
@@ -81,7 +81,7 @@ function parseIeConditionalStartComment(node, match /* , parseHtml */) {
  const { condition } = match.groups;
  return {
    kind: "ieConditionalStartComment",
-    condition: condition.trim().replaceAll(/\s+/gu, " "),
+    condition: condition.trim().replaceAll(/\s+/g, " "),
    sourceSpan: node.sourceSpan,
  };
 }
@@ -69,7 +69,7 @@ function normalizeAngularControlFlowBlock(node) {
    return;
  }

-  node.name = node.name.toLowerCase().replaceAll(/\s+/gu, " ").trim();
+  node.name = node.name.toLowerCase().replaceAll(/\s+/g, " ").trim();
  node.kind = "angularControlFlowBlock";

  if (!isNonEmptyArray(node.parameters)) {
@@ -157,7 +157,7 @@ function restoreNameAndValue(node) {
          attr.value = null;
        } else {
          attr.value = attr.valueSpan.toString();
-          if (/["']/u.test(attr.value[0])) {
+          if (/["']/.test(attr.value[0])) {
            attr.value = attr.value.slice(1, -1);
          }
        }
@@ -187,7 +187,7 @@ function extractInterpolation(ast, options) {
    return;
  }

-  const interpolationRegex = /\{\{(.+?)\}\}/su;
+  const interpolationRegex = /\{\{(.+?)\}\}/s;
  ast.walk((node) => {
    if (!canHaveInterpolation(node, options)) {
      return;
@@ -348,7 +348,7 @@ function addHasHtmComponentClosingTag(ast, options) {

    node.hasHtmComponentClosingTag =
      node.endSourceSpan &&
-      /^<\s*\/\s*\/\s*>$/u.test(
+      /^<\s*\/\s*\/\s*>$/.test(
        options.originalText.slice(
          node.endSourceSpan.start.offset,
          node.endSourceSpan.end.offset,
@@ -140,7 +140,6 @@ function printElement(path, options, print) {
          node.isIndentationSensitive)) &&
      new RegExp(
        String.raw`\n[\t ]{${options.tabWidth * (path.ancestors.length - 1)}}$`,
-        "u",
      ).test(node.lastChild.value)
    ) {
      return "";
@@ -192,7 +192,7 @@ function needsToBorrowNextOpeningTagStartMarker(node) {
 }

 function getPrettierIgnoreAttributeCommentData(value) {
-  const match = value.trim().match(/^prettier-ignore-attribute(?:\s+(.+))?$/su);
+  const match = value.trim().match(/^prettier-ignore-attribute(?:\s+(.+))?$/s);

  if (!match) {
    return false;
@@ -202,7 +202,7 @@ function getPrettierIgnoreAttributeCommentData(value) {
    return true;
  }

-  return match[1].split(/\s+/u);
+  return match[1].split(/\s+/);
 }

 function needsToBorrowParentOpeningTagEndMarker(node) {
@@ -356,7 +356,7 @@ function printOpeningTagStartMarker(node, options) {
      // Only lowercase HTML5 doctype in `.html` and `.htm` files
      if (node.value === "html") {
        const { filepath } = options;
-        if (filepath && /\.html?$/u.test(filepath)) {
+        if (filepath && /\.html?$/.test(filepath)) {
          return HTML5_DOCTYPE_START_MARKER;
        }
      }
@@ -90,7 +90,7 @@ function genericPrint(path, options, print) {
    case "text": {
      if (node.parent.kind === "interpolation") {
        // replace the trailing literalline with hardline for better readability
-        const trailingNewlineRegex = /\n[^\S\n]*$/u;
+        const trailingNewlineRegex = /\n[^\S\n]*$/;
        const hasTrailingNewline = trailingNewlineRegex.test(node.value);
        const value = hasTrailingNewline
          ? node.value.replace(trailingNewlineRegex, "")
@@ -115,7 +115,7 @@ function genericPrint(path, options, print) {
        group([
          printOpeningTagStart(node, options),
          " ",
-          node.value.replace(/^html\b/iu, "html").replaceAll(/\s+/gu, " "),
+          node.value.replace(/^html\b/i, "html").replaceAll(/\s+/g, " "),
        ]),
        printClosingTagEnd(node, options),
      ];
@@ -20,7 +20,7 @@ import {
 import isUnknownNamespace from "./is-unknown-namespace.js";

 const htmlTrimLeadingBlankLines = (string) =>
-  string.replaceAll(/^[\t\f\r ]*\n/gu, "");
+  string.replaceAll(/^[\t\f\r ]*\n/g, "");
 const htmlTrimPreserveIndentation = (string) =>
  htmlTrimLeadingBlankLines(htmlWhitespace.trimEnd(string));
 const getLeadingAndTrailingHtmlWhitespace = (string) => {
@@ -482,7 +482,7 @@ function getNodeCssStyleDisplay(node, options) {

  if (node.prev?.kind === "comment") {
    // <!-- display: block -->
-    const match = node.prev.value.match(/^\s*display:\s*([a-z]+)\s*$/u);
+    const match = node.prev.value.match(/^\s*display:\s*([a-z]+)\s*$/);
    if (match) {
      return match[1];
    }
@@ -614,7 +614,7 @@ function shouldUnquoteAttributeValue(node, options) {

  return (
    // Embedded HTML in JS: `` /* HTML */ `<my-element data-for={value}></my-element>` ``
-    /^PRETTIER_HTML_PLACEHOLDER_\d+_\d+_IN_JS$/u.test(value) ||
+    /^PRETTIER_HTML_PLACEHOLDER_\d+_\d+_IN_JS$/.test(value) ||
    // LWC `<div foo={value}></div>`
    (options.parser === "lwc" && value.startsWith("{") && value.endsWith("}"))
  );
@@ -118,10 +118,10 @@ function clean(original, cloned, parent) {
  if (
    original.type === "JSXAttribute" &&
    original.value?.type === "Literal" &&
-    /["']|&quot;|&apos;/u.test(original.value.value)
+    /["']|&quot;|&apos;/.test(original.value.value)
  ) {
    cloned.value.value = original.value.value.replaceAll(
-      /["']|&quot;|&apos;/gu,
+      /["']|&quot;|&apos;/g,
      '"',
    );
  }
@@ -2,7 +2,7 @@ function isGap(text, { parser }) {
  if (parser === "flow" || parser === "hermes" || parser === "babel-flow") {
    // Example: (a /* b */ /* : c */)
    //                gap ^^^^
-    text = text.replaceAll(/[\s(]/gu, "");
+    text = text.replaceAll(/[\s(]/g, "");
    return text === "" || text === "/*" || text === "/*::";
  }
 }
@@ -50,18 +50,16 @@ function replacePlaceholders(quasisDoc, expressionDocs) {
    }
    // When we have multiple placeholders in one line, like:
    // ${Child}${Child2}:not(:first-child)
-    return doc
-      .split(/@prettier-placeholder-(\d+)-id/u)
-      .map((component, idx) => {
-        // The placeholder is always at odd indices
-        if (idx % 2 === 0) {
-          return replaceEndOfLine(component);
-        }
+    return doc.split(/@prettier-placeholder-(\d+)-id/).map((component, idx) => {
+      // The placeholder is always at odd indices
+      if (idx % 2 === 0) {
+        return replaceEndOfLine(component);
+      }

-        // The component will always be a number at odd index
-        replaceCounter++;
-        return expressionDocs[component];
-      });
+      // The component will always be a number at odd index
+      replaceCounter++;
+      return expressionDocs[component];
+    });
  });
  return expressionDocs.length === replaceCounter ? newDoc : null;
 }
@@ -106,7 +104,7 @@ function isStyledIdentifier(node) {
 }

 function isStyledExtend(node) {
-  return /^[A-Z]/u.test(node.object.name) && node.property.name === "extend";
+  return /^[A-Z]/.test(node.object.name) && node.property.name === "extend";
 }

 /**
@@ -30,11 +30,11 @@ async function printEmbedGraphQL(textToDoc, print, path, options) {
      lines[numLines - 2].trim() === "";

    const commentsAndWhitespaceOnly = lines.every((line) =>
-      /^\s*(?:#[^\n\r]*)?$/u.test(line),
+      /^\s*(?:#[^\n\r]*)?$/.test(line),
    );

    // Bail out if an interpolation occurs within a comment.
-    if (!isLast && /#[^\n\r]*$/u.test(lines[numLines - 1])) {
+    if (!isLast && /#[^\n\r]*$/.test(lines[numLines - 1])) {
      return null;
    }

@@ -34,7 +34,7 @@ async function printEmbedHtmlLike(parser, textToDoc, print, path, options) {

  const placeholderRegex = new RegExp(
    composePlaceholder(String.raw`(\d+)`),
-    "gu",
+    "g",
  );
  let topLevelCount = 0;
  const doc = await textToDoc(text, {
@@ -60,7 +60,7 @@ async function printEmbedHtmlLike(parser, textToDoc, print, path, options) {
          component = uncookTemplateElementValue(component);
          if (options.__embeddedInHtml) {
            component = component.replaceAll(
-              /<\/(?=script\b)/giu,
+              /<\/(?=script\b)/gi,
              String.raw`<\/`,
            );
          }
@@ -76,8 +76,8 @@ async function printEmbedHtmlLike(parser, textToDoc, print, path, options) {
    return parts;
  });

-  const leadingWhitespace = /^\s/u.test(text) ? " " : "";
-  const trailingWhitespace = /\s$/u.test(text) ? " " : "";
+  const leadingWhitespace = /^\s/.test(text) ? " " : "";
+  const trailingWhitespace = /\s$/.test(text) ? " " : "";

  const linebreak =
    options.htmlWhitespaceSensitivity === "ignore"
@@ -9,13 +9,13 @@ import { escapeTemplateCharacters } from "../print/template-literal.js";
 async function printEmbedMarkdown(textToDoc, print, path /* , options*/) {
  const { node } = path;
  let text = node.quasis[0].value.raw.replaceAll(
-    /((?:\\\\)*)\\`/gu,
+    /((?:\\\\)*)\\`/g,
    (_, backslashes) => "\\".repeat(backslashes.length / 2) + "`",
  );
  const indentation = getIndentation(text);
  const hasIndent = indentation !== "";
  if (hasIndent) {
-    text = text.replaceAll(new RegExp(`^${indentation}`, "gmu"), "");
+    text = text.replaceAll(new RegExp(`^${indentation}`, "gm"), "");
  }
  const doc = escapeTemplateCharacters(
    await textToDoc(text, { parser: "markdown", __inJsTemplate: true }),
@@ -30,7 +30,7 @@ async function printEmbedMarkdown(textToDoc, print, path /* , options*/) {
 }

 function getIndentation(str) {
-  const firstMatchedIndent = str.match(/^([^\S\n]*)\S/mu);
+  const firstMatchedIndent = str.match(/^([^\S\n]*)\S/m);
  return firstMatchedIndent === null ? "" : firstMatchedIndent[1];
 }

@@ -18,7 +18,7 @@ function shouldAddParenthesesToIdentifier(path) {
  //     f((a + b) / 2)  vs  f(a + b / 2)
  if (
    node.extra?.parenthesized &&
-    /^PRETTIER_HTML_PLACEHOLDER_\d+_\d+_IN_JS$/u.test(node.name)
+    /^PRETTIER_HTML_PLACEHOLDER_\d+_\d+_IN_JS$/.test(node.name)
  ) {
    return true;
  }
@@ -44,7 +44,7 @@ function createParseError(error) {

  const { line, column } = loc;

-  return createError(message.replace(/ \(\d+:\d+\)$/u, ""), {
+  return createError(message.replace(/ \(\d+:\d+\)$/, ""), {
    loc: {
      start: { line, column: column + 1 },
    },
@@ -72,7 +72,7 @@ const appendPlugins = (plugins, options = parseOptions) => ({

 // Similar to babel
 // https://github.com/babel/babel/pull/7934/files#diff-a739835084910b0ee3ea649df5a4d223R67
-const FLOW_PRAGMA_REGEX = /@(?:no)?flow\b/u;
+const FLOW_PRAGMA_REGEX = /@(?:no)?flow\b/;
 function isFlowFile(text, filepath) {
  if (filepath?.endsWith(".js.flow")) {
    return true;
@@ -135,7 +135,7 @@ function createParse({ isExpression = false, optionsCombinations }) {
      }));
    }

-    const shouldEnableV8intrinsicPlugin = /%[A-Z]/u.test(text);
+    const shouldEnableV8intrinsicPlugin = /%[A-Z]/.test(text);
    if (text.includes("|>")) {
      const conflictsPlugins = shouldEnableV8intrinsicPlugin
        ? [...pipelineOperatorPlugins, v8intrinsicPlugin]
@@ -67,7 +67,7 @@ async function parseWithOptions(filepath, text, options) {
      error.severity === "Error" &&
      (error.message ===
        "A 'return' statement can only be used within a function body." ||
-        /^Identifier `.*` has already been declared$/u.test(error.message))
+        /^Identifier `.*` has already been declared$/.test(error.message))
    ) {
      continue;
    }
@@ -103,7 +103,7 @@ function getLanguageCombinations(text, options) {
  const filepath = options?.filepath;

  if (typeof filepath === "string") {
-    if (/\.(?:jsx|tsx)$/iu.test(filepath)) {
+    if (/\.(?:jsx|tsx)$/i.test(filepath)) {
      return ["tsx"];
    }

@@ -50,7 +50,7 @@ function createParseError(error) {

 // https://typescript-eslint.io/packages/parser/#jsx
 const isKnownFileType = (filepath) =>
-  filepath && /\.(?:js|mjs|cjs|jsx|ts|mts|cts|tsx)$/iu.test(filepath);
+  filepath && /\.(?:js|mjs|cjs|jsx|ts|mts|cts|tsx)$/i.test(filepath);

 function getParseOptionsCombinations(text, filepath) {
  let combinations = [{ ...baseParseOptions, filePath: filepath }];
@@ -8,5 +8,5 @@ export default new RegExp(
    "|",
    "^[^/]{2}.*/>", // Contains "/>" on line not starting with "//"
  ].join(""),
-  "mu",
+  "m",
 );
@@ -16,11 +16,11 @@ export function getSourceType(filepath) {

  filepath = filepath.toLowerCase();

-  if (/\.(?:mjs|mts)$/iu.test(filepath)) {
+  if (/\.(?:mjs|mts)$/i.test(filepath)) {
    return SOURCE_TYPE_MODULE;
  }

-  if (/\.(?:cjs|cts)$/iu.test(filepath)) {
+  if (/\.(?:cjs|cts)$/i.test(filepath)) {
    return SOURCE_TYPE_COMMONJS;
  }
 }
@@ -39,7 +39,7 @@ function printAngular(path, options, print) {
        "body",
      );
    case "NGMicrosyntaxKey":
-      return /^[$_a-z][\w$]*(?:-[$_a-z][\w$])*$/iu.test(node.name)
+      return /^[$_a-z][\w$]*(?:-[$_a-z][\w$])*$/i.test(node.name)
        ? node.name
        : JSON.stringify(node.name);
    case "NGMicrosyntaxExpression":
@@ -228,7 +228,7 @@ function printEstree(path, options, print, args) {
    case "UnaryExpression": {
      const parts = [node.operator];

-      if (/[a-z]$/u.test(node.operator)) {
+      if (/[a-z]$/.test(node.operator)) {
        parts.push(" ");
      }

@@ -347,7 +347,7 @@ function printJsxChildren(
        // Starts with whitespace
        if (words[0] === "") {
          words.shift();
-          if (/\n/u.test(words[0])) {
+          if (/\n/.test(words[0])) {
            pushLine(
              separatorWithWhitespace(
                isFacebookTranslationTag,
@@ -383,7 +383,7 @@ function printJsxChildren(
        }

        if (endWhitespace !== undefined) {
-          if (/\n/u.test(endWhitespace)) {
+          if (/\n/.test(endWhitespace)) {
            pushLine(
              separatorWithWhitespace(
                isFacebookTranslationTag,
@@ -405,10 +405,10 @@ function printJsxChildren(
            ),
          );
        }
-      } else if (/\n/u.test(text)) {
+      } else if (/\n/.test(text)) {
        // Keep (up to one) blank line between tags/expressions/text.
        // Note: We don't keep blank lines between text elements.
-        if (text.match(/\n/gu).length > 1) {
+        if (text.match(/\n/g).length > 1) {
          pushLine(hardline);
        }
      } else {
@@ -864,7 +864,7 @@ function isMeaningfulJsxText(node) {
  return (
    node.type === "JSXText" &&
    (jsxWhitespace.hasNonWhitespaceCharacter(getRaw(node)) ||
-      !/\n/u.test(getRaw(node)))
+      !/\n/.test(getRaw(node)))
  );
 }

@@ -70,7 +70,7 @@ function printTypeScriptMappedType(path, options, print) {
      start + 1,
      locStart(node.key),
    );
-    const nextTokenIndex = start + 1 + textAfter.search(/\S/u);
+    const nextTokenIndex = start + 1 + textAfter.search(/\S/);
    if (hasNewlineInRange(options.originalText, start, nextTokenIndex)) {
      shouldBreak = true;
    }
@@ -272,7 +272,7 @@ function printMemberChain(path, options, print) {
  // letter or just a sequence of _$. The rationale is that they are
  // likely to be factories.
  function isFactory(name) {
-    return /^[A-Z]|^[$_]+$/u.test(name);
+    return /^[A-Z]|^[$_]+$/.test(name);
  }

  // In case the Identifier is shorter than tab width, we can keep the
@@ -10,7 +10,7 @@ const needsQuoteProps = new WeakMap();

 // Matches “simple” numbers like `123` and `2.5` but not `1_000`, `1e+100` or `0b10`.
 function isSimpleNumber(numberString) {
-  return /^(?:\d+|\d+\.\d+)$/u.test(numberString);
+  return /^(?:\d+|\d+\.\d+)$/.test(numberString);
 }

 // Note: Quoting/unquoting numbers in TypeScript is not safe.
@@ -169,7 +169,7 @@ function printPropertyKey(path, options, print) {
      () =>
        printComments(
          path,
-          /^\d/u.test(key.value) ? printNumber(key.value) : key.value,
+          /^\d/.test(key.value) ? printNumber(key.value) : key.value,
          options,
        ),
      "key",
@@ -90,7 +90,7 @@ function printJestEachTemplateLiteral(path, options, print) {
   * ${2} | ${1} | ${3}
   */
  const { node } = path;
-  const headerNames = node.quasis[0].value.raw.trim().split(/\s*\|\s*/u);
+  const headerNames = node.quasis[0].value.raw.trim().split(/\s*\|\s*/);
  if (
    headerNames.length > 1 ||
    headerNames.some((headerName) => headerName.length > 0)
@@ -275,7 +275,7 @@ function escapeTemplateCharacters(doc, raw) {
  return mapDoc(doc, (currentDoc) => {
    if (typeof currentDoc === "string") {
      return raw
-        ? currentDoc.replaceAll(/(\\*)`/gu, "$1$1\\`")
+        ? currentDoc.replaceAll(/(\\*)`/g, "$1$1\\`")
        : uncookTemplateElementValue(currentDoc);
    }

@@ -284,7 +284,7 @@ function escapeTemplateCharacters(doc, raw) {
 }

 function uncookTemplateElementValue(cookedValue) {
-  return cookedValue.replaceAll(/([\\`]|\$\{)/gu, String.raw`\$1`);
+  return cookedValue.replaceAll(/([\\`]|\$\{)/g, String.raw`\$1`);
 }

 /**
@@ -297,7 +297,7 @@ function uncookTemplateElementValue(cookedValue) {
 *
 * Ref: https://github.com/facebook/jest/pull/6102
 */
-const jestEachTriggerRegex = /^[fx]?(?:describe|it|test)$/u;
+const jestEachTriggerRegex = /^[fx]?(?:describe|it|test)$/;
 function isJestEachTemplateLiteral({ node, parent }) {
  return (
    node.type === "TemplateLiteral" &&
@@ -39,7 +39,7 @@ function shouldForceTrailingComma(path, options, paramsKey) {
    node.type.startsWith("TS") &&
    !node[paramsKey][0].constraint &&
    path.parent.type === "ArrowFunctionExpression" &&
-    !(options.filepath && /\.ts$/u.test(options.filepath))
+    !(options.filepath && /\.ts$/.test(options.filepath))
  );
 }

@@ -19,7 +19,7 @@ function isTypeCastComment(comment) {
        // TypeScript expects the type to be enclosed in curly brackets, however
        // Closure Compiler accepts types in parens and even without any delimiters at all.
        // That's why we just search for "@type" and "@satisfies".
-        /@(?:type|satisfies)\b/u.test(comment.value),
+        /@(?:type|satisfies)\b/.test(comment.value),
    );
  }

@@ -36,7 +36,7 @@ function clean(original, cloned, parent) {
  }

  if (original.type === "wikiLink") {
-    cloned.value = original.value.trim().replaceAll(/[\t\n]+/gu, " ");
+    cloned.value = original.value.trim().replaceAll(/[\t\n]+/g, " ");
  }

  if (
@@ -66,7 +66,7 @@ function clean(original, cloned, parent) {
      original.type === "image") &&
    original.title
  ) {
-    cloned.title = original.title.replaceAll(/\\(?=["')])/gu, "");
+    cloned.title = original.title.replaceAll(/\\(?=["')])/g, "");
  }

  // for insert pragma
@@ -22,11 +22,11 @@
 * THE SOFTWARE.
 */

-const IMPORT_REGEX = /^import\s/u;
-const EXPORT_REGEX = /^export\s/u;
+const IMPORT_REGEX = /^import\s/;
+const EXPORT_REGEX = /^export\s/;
 const BLOCKS_REGEX = String.raw`[a-z][a-z0-9]*(\.[a-z][a-z0-9]*)*|`;
-const COMMENT_REGEX = /<!---->|<!---?[^>-](?:-?[^-])*-->/u;
-const ES_COMMENT_REGEX = /^\{\s*\/\*(.*)\*\/\s*\}/u;
+const COMMENT_REGEX = /<!---->|<!---?[^>-](?:-?[^-])*-->/;
+const ES_COMMENT_REGEX = /^\{\s*\/\*(.*)\*\/\s*\}/;
 const EMPTY_NEWLINE = "\n\n";

 const isImport = (text) => IMPORT_REGEX.test(text);
@@ -10,7 +10,7 @@ const liquid = function () {
  proto.inlineTokenizers.liquid = tokenizer;

  function tokenizer(eat, value) {
-    const match = value.match(/^(\{%.*?%\}|\{\{.*?\}\})/su);
+    const match = value.match(/^(\{%.*?%\}|\{\{.*?\}\})/s);

    if (match) {
      return eat(match[0])({
@@ -5,7 +5,7 @@
 */
 const wikiLink = function () {
  const entityType = "wikiLink";
-  const wikiLinkRegex = /^\[\[(?<linkContents>.+?)\]\]/su;
+  const wikiLinkRegex = /^\[\[(?<linkContents>.+?)\]\]/s;
  const proto = this.Parser.prototype;
  const methods = proto.inlineMethods;
  methods.splice(methods.indexOf("link"), 0, entityType);
@@ -101,7 +101,7 @@ function printMdast(path, options, print) {

      const proseWrap =
        // leading char that may cause different syntax
-        next && /^>|^(?:[*+-]|#{1,6}|\d+[).])$/u.test(next.value)
+        next && /^>|^(?:[*+-]|#{1,6}|\d+[).])$/.test(next.value)
          ? "never"
          : options.proseWrap;

@@ -140,7 +140,7 @@ function printMdast(path, options, print) {
      const padding =
        code.startsWith("`") ||
        code.endsWith("`") ||
-        (/^[\n ]/u.test(code) && /[\n ]$/u.test(code) && /[^\n ]/u.test(code))
+        (/^[\n ]/.test(code) && /[\n ]$/.test(code) && /[^\n ]/.test(code))
          ? " "
          : "";
      return [backtickString, padding, code, padding, backtickString];
@@ -150,7 +150,7 @@ function printMdast(path, options, print) {
      if (options.proseWrap === "preserve") {
        contents = node.value;
      } else {
-        contents = node.value.replaceAll(/[\t\n]+/gu, " ");
+        contents = node.value.replaceAll(/[\t\n]+/g, " ");
      }

      return ["[[", contents, "]]"];
@@ -233,7 +233,7 @@ function printMdast(path, options, print) {
      const { parent, isLast } = path;
      const value =
        parent.type === "root" && isLast ? node.value.trimEnd() : node.value;
-      const isHtmlComment = /^<!--.*-->$/su.test(value);
+      const isHtmlComment = /^<!--.*-->$/s.test(value);

      return replaceEndOfLine(
        value,
@@ -327,7 +327,7 @@ function printMdast(path, options, print) {
    case "tableCell":
      return printChildren(path, options, print);
    case "break":
-      return /\s/u.test(options.originalText[node.position.start.offset])
+      return /\s/.test(options.originalText[node.position.start.offset])
        ? ["  ", markAsRoot(literalline)]
        : ["\\", hardline];
    case "liquidNode":
@@ -471,7 +471,6 @@ function printUrl(url, dangerousCharOrChars = []) {

  return new RegExp(
    dangerousChars.map((x) => escapeStringRegexp(x)).join("|"),
-    "u",
  ).test(url)
    ? `<${encodeUrl(url, "<>")}>`
    : url;
@@ -486,7 +485,7 @@ function printTitle(title, options, printSpace = true) {
  }

  // title is escaped after `remark-parse` v7
-  title = title.replaceAll(/\\(?=["')])/gu, "");
+  title = title.replaceAll(/\\(?=["')])/g, "");

  if (title.includes('"') && title.includes("'") && !title.includes(")")) {
    return `(${title})`; // avoid escaped quotes
@@ -3,7 +3,7 @@ import { getOrderedListItemInfo, mapAst, splitText } from "../utilities.js";

 // 0x0 ~ 0x10ffff
 const isSingleCharRegex = /^\\?.$/su;
-const isNewLineBlockquoteRegex = /^\n *>[ >]*$/u;
+const isNewLineBlockquoteRegex = /^\n *>[ >]*$/;

 function preprocess(ast, options) {
  ast = restoreUnescapedCharacter(ast, options);
@@ -116,7 +116,7 @@ function transformIndentedCodeblockAndMarkItsParentList(ast, options) {
  return mapAst(ast, (node, index, parentStack) => {
    if (node.type === "code") {
      // the first char may point to `\n`, e.g. `\n\t\tbar`, just ignore it
-      const isIndented = /^\n?(?: {4,}|\t)/u.test(
+      const isIndented = /^\n?(?: {4,}|\t)/.test(
        options.originalText.slice(
          node.position.start.offset,
          node.position.end.offset,
@@ -45,7 +45,7 @@ function printWord(path) {
      ))
  ) {
    // backslash is parsed as part of autolinks, so we need to remove it
-    escapedValue = escapedValue.replace(/^(\\?[*_])+/u, (prefix) =>
+    escapedValue = escapedValue.replace(/^(\\?[*_])+/, (prefix) =>
      prefix.replaceAll("\\", ""),
    );
  }
@@ -65,13 +65,13 @@ function splitText(text) {
  /** @type {Array<TextNode>} */
  const nodes = [];

-  const tokens = text.split(/([\t\n ]+)/u);
+  const tokens = text.split(/([\t\n ]+)/);
  for (const [index, token] of tokens.entries()) {
    // whitespace
    if (index % 2 === 1) {
      nodes.push({
        type: "whitespace",
-        value: /\n/u.test(token) ? "\n" : " ",
+        value: /\n/.test(token) ? "\n" : " ",
      });
      continue;
    }
@@ -165,7 +165,7 @@ function splitText(text) {
      lastNode?.type === "word" &&
      !isBetween(KIND_NON_CJK, KIND_CJK_PUNCTUATION) &&
      // disallow leading/trailing full-width whitespace
-      ![lastNode.value, node.value].some((value) => /\u3000/u.test(value))
+      ![lastNode.value, node.value].some((value) => /\u3000/.test(value))
    ) {
      nodes.push({ type: "whitespace", value: "" });
    }
@@ -187,7 +187,7 @@ function getOrderedListItemInfo(orderListItem, options) {
  );

  const { numberText, leadingSpaces } = text.match(
-    /^\s*(?<numberText>\d+)(\.|\))(?<leadingSpaces>\s*)/u,
+    /^\s*(?<numberText>\d+)(\.|\))(?<leadingSpaces>\s*)/,
  ).groups;

  return { number: Number(numberText), leadingSpaces };
@@ -257,9 +257,7 @@ function isPrettierIgnore(node) {
  let match;

  if (node.type === "html") {
-    match = node.value.match(
-      /^<!--\s*prettier-ignore(?:-(start|end))?\s*-->$/u,
-    );
+    match = node.value.match(/^<!--\s*prettier-ignore(?:-(start|end))?\s*-->$/);
  } else {
    let comment;

@@ -274,7 +272,7 @@ function isPrettierIgnore(node) {
    }

    if (comment) {
-      match = comment.value.match(/^prettier-ignore(?:-(start|end))?$/u);
+      match = comment.value.match(/^prettier-ignore(?:-(start|end))?$/);
    }
  }

@@ -29,7 +29,7 @@ function clean(original, cloned /* , parent */) {
      if (original.chomping === "keep") {
        cloned.value = original.value
          .split("\n")
-          .map((line) => line.replace(/[ \t]+$/u, ""))
+          .map((line) => line.replace(/[ \t]+$/, ""))
          .join("\n");
      }
      break;
@@ -7,7 +7,7 @@ function embed(path, options) {
  if (
    node.type === "root" &&
    options.filepath &&
-    /(?:[/\\]|^)\.(?:prettier|stylelint|lintstaged)rc$/u.test(options.filepath)
+    /(?:[/\\]|^)\.(?:prettier|stylelint|lintstaged)rc$/.test(options.filepath)
  ) {
    return async (textToDoc) => {
      const doc = await textToDoc(options.originalText, { parser: "json" });
@@ -173,7 +173,7 @@ function isAbsolutelyPrintedAsSingleLineNode(node, options) {

  if (
    // backslash-newline
-    /\\$/mu.test(
+    /\\$/m.test(
      options.originalText.slice(
        node.position.start.offset,
        node.position.end.offset,
@@ -187,7 +187,7 @@ function isAbsolutelyPrintedAsSingleLineNode(node, options) {
    case "never":
      return !node.value.includes("\n");
    case "always":
-      return !/[\n ]/u.test(node.value);
+      return !/[\n ]/.test(node.value);
    default:
      /* c8 ignore next */
      return false;
@@ -266,7 +266,7 @@ function printNode(path, options, print) {

      if (
        (node.type === "quoteSingle" && raw.includes("\\")) ||
-        (node.type === "quoteDouble" && /\\[^"]/u.test(raw))
+        (node.type === "quoteDouble" && /\\[^"]/.test(raw))
      ) {
        // only quoteDouble can use escape chars
        // and quoteSingle do not need to escape backslashes
@@ -39,7 +39,7 @@ function isNextLineEmpty(node, text) {
      newlineCount++;
    }

-    if (newlineCount === 1 && /\S/u.test(char)) {
+    if (newlineCount === 1 && /\S/.test(char)) {
      return false;
    }

@@ -145,7 +145,7 @@ function hasEndComments(node) {
@param {string} text
 */
 function splitWithSingleSpace(text) {
-  return text ? text.split(/(?<!^| ) (?! |$)/u) : [];
+  return text ? text.split(/(?<!^| ) (?! |$)/) : [];
 }

 /**
@@ -207,7 +207,7 @@ function getBlockValueLineContents(
      : options.originalText
          .slice(node.position.start.offset, node.position.end.offset)
          // exclude open line `>` or `|`
-          .match(/^[^\n]*\n(.*)$/su)[1];
+          .match(/^[^\n]*\n(.*)$/s)[1];

  if (content === "") {
    return [];
@@ -216,7 +216,7 @@ function getBlockValueLineContents(
  /** @type {number} */
  let leadingSpaceCount;
  if (node.indent === null) {
-    const matches = content.match(/^(?<leadingSpace> *)[^\n\r ]/mu);
+    const matches = content.match(/^(?<leadingSpace> *)[^\n\r ]/m);
    leadingSpaceCount = matches
      ? matches.groups.leadingSpace.length
      : Number.POSITIVE_INFINITY;
@@ -243,11 +243,11 @@ function getBlockValueLineContents(
      index > 0 &&
      words.length > 0 &&
      rawLineContents[index - 1].length > 0 &&
-      !/^\s/u.test(words[0]) &&
+      !/^\s/.test(words[0]) &&
      // This test against a `string[]`, should be a mistake
      // originally introduced in https://github.com/prettier/prettier/pull/4742/files#diff-a4dc2e1922e1d8d5ac20818480f777c9a2d5af739eaa3a0409b08bf29a9d0f74R282
      // @ts-expect-error -- see comment above
-      !/^\s|\s$/u.test(lines.at(-1))
+      !/^\s|\s$/.test(lines.at(-1))
    ) {
      lines[lines.length - 1] = [...lines.at(-1), ...words];
    } else {
@@ -259,7 +259,7 @@ function getBlockValueLineContents(
    const words = [];
    for (const word of originalWords) {
      // disallow trailing spaces
-      if (words.length > 0 && /\s$/u.test(words.at(-1))) {
+      if (words.length > 0 && /\s$/.test(words.at(-1))) {
        words[words.length - 1] += " " + word;
      } else {
        words.push(word);
@@ -286,9 +286,7 @@ function getBlockValueLineContents(

    let trailingNewlineCount = 0;
    for (let i = lineContents.length - 1; i >= 0; i--) {
-      if (
-        lineContents[i].every((line) => line.replace(/[ \t]+$/u, "") === "")
-      ) {
+      if (lineContents[i].every((line) => line.replace(/[ \t]+$/, "") === "")) {
        trailingNewlineCount++;
      } else {
        break;
@@ -244,7 +244,7 @@ function attachComments(ast, options) {
  }
 }

-const isAllEmptyAndNoLineBreak = (text) => !/[\S\n\u2028\u2029]/u.test(text);
+const isAllEmptyAndNoLineBreak = (text) => !/[\S\n\u2028\u2029]/.test(text);
 function isOwnLineComment(text, options, decoratedComments, commentIndex) {
  const { comment, precedingNode } = decoratedComments[commentIndex];
  const { locStart, locEnd } = options;
@@ -325,7 +325,7 @@ function breakTies(tiesToBreak, options) {

    const gap = options.originalText.slice(options.locEnd(comment), gapEndPos);

-    if (options.printer.isGap?.(gap, options) ?? /^[\s(]*$/u.test(gap)) {
+    if (options.printer.isGap?.(gap, options) ?? /^[\s(]*$/.test(gap)) {
      gapEndPos = options.locStart(comment);
    } else {
      // The gap string contained something other than whitespace or open
@@ -192,7 +192,7 @@ async function formatRange(originalText, opts) {
    rangeStart,
    text.lastIndexOf("\n", rangeStart) + 1,
  );
-  const indentString = text.slice(rangeStart2, rangeStart).match(/^\s*/u)[0];
+  const indentString = text.slice(rangeStart2, rangeStart).match(/^\s*/)[0];

  const alignmentSize = getAlignmentSize(indentString, opts.tabWidth);

@@ -65,7 +65,7 @@ function getFrontMatter(text) {
  const frontMatterEndIndex = endDelimiterIndex + 1 + DELIMITER_LENGTH;

  const nextCharacter = text.charAt(frontMatterEndIndex + 1);
-  if (!/\s?/u.test(nextCharacter)) {
+  if (!/\s?/.test(nextCharacter)) {
    return;
  }

@@ -201,12 +201,12 @@ function calculateRange(text, opts, ast) {
  assert.ok(end > start);
  // Contract the range so that it has non-whitespace characters at its endpoints.
  // This ensures we can format a range that doesn't end on a node.
-  const firstNonWhitespaceCharacterIndex = text.slice(start, end).search(/\S/u);
+  const firstNonWhitespaceCharacterIndex = text.slice(start, end).search(/\S/);
  const isAllWhitespace = firstNonWhitespaceCharacterIndex === -1;
  if (!isAllWhitespace) {
    start += firstNonWhitespaceCharacterIndex;
    for (; end > start; --end) {
-      if (/\S/u.test(text[end - 1])) {
+      if (/\S/.test(text[end - 1])) {
        break;
      }
    }
@@ -2,7 +2,7 @@
@param {string | URL} file
@returns {string}
 */
-const getFileBasename = (file) => String(file).split(/[/\\]/u).pop();
+const getFileBasename = (file) => String(file).split(/[/\\]/).pop();

 // Ideally, we should only allow `URL` with `file:` protocol and
 // string starts with `file:`, but `URL` is missing in some environments
@@ -14,7 +14,7 @@ function getIndentSize(value, tabWidth) {

  return getAlignmentSize(
    // All the leading whitespaces
-    value.slice(lastNewlineIndex + 1).match(/^[\t ]*/u)[0],
+    value.slice(lastNewlineIndex + 1).match(/^[\t ]*/)[0],
    tabWidth,
  );
 }
@@ -33,13 +33,13 @@ function getInterpreter(file) {
  }

  // #!/bin/env node, #!/usr/bin/env node
-  const m1 = firstLine.match(/^#!\/(?:usr\/)?bin\/env\s+(\S+)/u);
+  const m1 = firstLine.match(/^#!\/(?:usr\/)?bin\/env\s+(\S+)/);
  if (m1) {
    return m1[1];
  }

  // #!/bin/node, #!/usr/bin/node, #!/usr/local/bin/node
-  const m2 = firstLine.match(/^#!\/(?:usr\/(?:local\/)?)?bin\/(\S+)/u);
+  const m2 = firstLine.match(/^#!\/(?:usr\/(?:local\/)?)?bin\/(\S+)/);
  if (m2) {
    return m2[1];
  }
@@ -7,7 +7,7 @@ import escapeStringRegexp from "escape-string-regexp";
 */
 function getMaxContinuousCount(text, searchString) {
  let results = text.matchAll(
-    new RegExp(`(?:${escapeStringRegexp(searchString)})+`, "gu"),
+    new RegExp(`(?:${escapeStringRegexp(searchString)})+`, "g"),
  );

  // TODO: Use `Iterator#reduce` when we drop support for Node.js < 22
@@ -11,7 +11,7 @@ import escapeStringRegexp from "escape-string-regexp";
 */
 function getMinNotPresentContinuousCount(text, searchString) {
  const matches = text.match(
-    new RegExp(`(${escapeStringRegexp(searchString)})+`, "gu"),
+    new RegExp(`(${escapeStringRegexp(searchString)})+`, "g"),
  );

  if (matches === null) {
@@ -7,7 +7,7 @@ import {
 } from "get-east-asian-width";
 import narrowEmojis from "./narrow-emojis.evaluate.js";

-const notAsciiRegex = /[^\x20-\x7F]/u;
+const notAsciiRegex = /[^\x20-\x7F]/;
 const narrowEmojisSet = new Set(narrowEmojis);

 // Similar to https://github.com/sindresorhus/string-width
@@ -4,7 +4,7 @@ import { DOUBLE_QUOTE, SINGLE_QUOTE } from "./get-preferred-quote.js";

 // Matches _any_ escape and unescaped quotes (both single and double).
 // Matching `\` in first group, so we won't treat `\\"` as escaped quote.
-const REGEX = /\\(["'\\])|(["'])/gu;
+const REGEX = /\\(["'\\])|(["'])/g;

 /**
 * @param {string} rawText
@@ -8,7 +8,6 @@ export const FORMAT_PRAGMA_TO_INSERT = FORMAT_PRAGMAS[0];

 export const YAML_IS_PRAGMA_REGEXP = new RegExp(
  String.raw`^\s*@(?:${FORMAT_PRAGMAS.join("|")})\s*$`,
-  "u",
 );

 export const [YAML_HAS_PRAGMA_REGEXP, YAML_HAS_IGNORE_PRAGMA_REGEXP] = [
@@ -16,10 +15,7 @@ export const [YAML_HAS_PRAGMA_REGEXP, YAML_HAS_IGNORE_PRAGMA_REGEXP] = [
  FORMAT_IGNORE_PRAGMAS,
 ].map(
  (pragmas) =>
-    new RegExp(
-      String.raw`^\s*#[^\S\n]*@(?:${pragmas.join("|")})\s*?(?:\n|$)`,
-      "u",
-    ),
+    new RegExp(String.raw`^\s*#[^\S\n]*@(?:${pragmas.join("|")})\s*?(?:\n|$)`),
 );

 export const [GRAPHQL_HAS_PRAGMA_REGEXP, GRAPHQL_HAS_IGNORE_PRAGMA_REGEXP] = [
@@ -27,10 +23,7 @@ export const [GRAPHQL_HAS_PRAGMA_REGEXP, GRAPHQL_HAS_IGNORE_PRAGMA_REGEXP] = [
  FORMAT_IGNORE_PRAGMAS,
 ].map(
  (pragmas) =>
-    new RegExp(
-      String.raw`^\s*#[^\S\n]*@(?:${pragmas.join("|")})\s*(?:\n|$)`,
-      "u",
-    ),
+    new RegExp(String.raw`^\s*#[^\S\n]*@(?:${pragmas.join("|")})\s*(?:\n|$)`),
 );

 export const [HTML_HAS_PRAGMA_REGEXP, HTML_HAS_IGNORE_PRAGMA_REGEXP] = [
@@ -38,7 +31,7 @@ export const [HTML_HAS_PRAGMA_REGEXP, HTML_HAS_IGNORE_PRAGMA_REGEXP] = [
  FORMAT_IGNORE_PRAGMAS,
 ].map(
  (pragmas) =>
-    new RegExp(String.raw`^\s*<!--\s*@(?:${pragmas.join("|")})\s*-->`, "u"),
+    new RegExp(String.raw`^\s*<!--\s*@(?:${pragmas.join("|")})\s*-->`),
 );

 export const [MARKDOWN_HAS_PRAGMA_REGEXP, MARKDOWN_HAS_IGNORE_PRAGMA_REGEXP] = [
@@ -52,6 +45,6 @@ export const [MARKDOWN_HAS_PRAGMA_REGEXP, MARKDOWN_HAS_IGNORE_PRAGMA_REGEXP] = [
      String.raw`\{\s*\/\*\s*${pragma}\s*\*\/\s*\}`,
      `<!--.*\r?\n[\\s\\S]*(^|\n)[^\\S\n]*${pragma}[^\\S\n]*($|\n)[\\s\\S]*\n.*-->`,
    ].join("|"),
-    "mu",
+    "m",
  );
 });
@@ -6,15 +6,15 @@ function printNumber(rawNumber) {
    rawNumber
      .toLowerCase()
      // Remove unnecessary plus and zeroes from scientific notation.
-      .replace(/^([+-]?[\d.]+e)(?:\+|(-))?0*(?=\d)/u, "$1$2")
+      .replace(/^([+-]?[\d.]+e)(?:\+|(-))?0*(?=\d)/, "$1$2")
      // Remove unnecessary scientific notation (1e0).
-      .replace(/^([+-]?[\d.]+)e[+-]?0+$/u, "$1")
+      .replace(/^([+-]?[\d.]+)e[+-]?0+$/, "$1")
      // Make sure numbers always start with a digit.
-      .replace(/^([+-])?\./u, "$10.")
+      .replace(/^([+-])?\./, "$10.")
      // Remove extraneous trailing decimal zeroes.
-      .replace(/(\.\d+?)0+(?=e|$)/u, "$1")
+      .replace(/(\.\d+?)0+(?=e|$)/, "$1")
      // Remove trailing dot.
-      .replace(/\.(?=e|$)/u, "")
+      .replace(/\.(?=e|$)/, "")
  );
 }