Fix ignored forX initializer (#20204)

changelog_unreleased/javascript/20204.md

@@ -0,0 +1,13 @@
+#### Fix `prettier-ignore`d `for` initializer (#20204 by @fisker)
+
+<!-- prettier-ignore -->
+```jsx
+// Input
+for (/* prettier-ignore */ let i  = 0; i < 1; i++) {}
+
+// Prettier stable
+for (/* prettier-ignore */ let i  = 0;; i < 1; i++) {}
+
+// Prettier main
+for (/* prettier-ignore */ let i  = 0; i < 1; i++) {}
+```

src/language-js/location/index.js

@@ -1,8 +1,4 @@
 export { hasSameLoc, hasSameLocStart } from "./comparison.js";
 export { locEndWithFullText } from "./end-with-full-text.js";
-export {
-  locEnd,
-  shouldAddContentEnd,
-  shouldIgnoredNodePrintSemicolon,
-} from "./overrides.js";
+export { locEnd, shouldAddContentEnd } from "./overrides.js";
 export { locStart } from "./start.js";

src/language-js/location/overrides.js

@@ -51,40 +51,6 @@ const overrides =
 
 const shouldAddContentEnd = createTypeCheckFunction(nodeTypesWithContentEnd);
 
-const shouldIgnoredNodePrintSemicolon = (node) => {
-  if (shouldAddContentEnd(node) && node.__contentEnd) {
-    return true;
-  }
-
-  const { type } = node;
-
-  if (
-    type === "BreakStatement" ||
-    type === "ContinueStatement" ||
-    type === "DebuggerStatement" ||
-    type === "VariableDeclaration"
-  ) {
-    return true;
-  }
-
-  if (type === "IfStatement") {
-    return shouldIgnoredNodePrintSemicolon(node.alternate ?? node.consequent);
-  }
-
-  if (
-    type === "ForInStatement" ||
-    type === "ForOfStatement" ||
-    type === "ForStatement" ||
-    type === "LabeledStatement" ||
-    type === "WithStatement" ||
-    type === "WhileStatement"
-  ) {
-    return shouldIgnoredNodePrintSemicolon(node.body);
-  }
-
-  return false;
-};
-
 /**
 @param {Node | Comment} node
 @return {number}
@@ -116,4 +82,4 @@ function locEnd(node) {
   );
 }
 
-export { locEnd, shouldAddContentEnd, shouldIgnoredNodePrintSemicolon };
+export { locEnd, shouldAddContentEnd };

src/language-js/print/ignored.js

@@ -1,17 +1,14 @@
 import { indent, softline } from "../../document/index.js";
 import isNonEmptyArray from "../../utilities/is-non-empty-array.js";
-import {
-  locEnd,
-  locStart,
-  shouldIgnoredNodePrintSemicolon,
-} from "../location/index.js";
+import { locEnd, locStart } from "../location/index.js";
 import { shouldExpressionStatementPrintLeadingSemicolon } from "../semicolon/semicolon.js";
+import { shouldIgnoredNodePrintSemicolon } from "../semicolon/should-ignored-node-print-semicolon.js";
 
 function printIgnored(path, options /* , print*/) {
   const { node } = path;
   let text = options.originalText.slice(locStart(node), locEnd(node));
 
-  if (options.semi && shouldIgnoredNodePrintSemicolon(node)) {
+  if (options.semi && shouldIgnoredNodePrintSemicolon(path)) {
     text += ";";
   } else if (shouldExpressionStatementPrintLeadingSemicolon(path, options)) {
     text = `;${text}`;

src/language-js/print/variable-declaration.js

@@ -1,5 +1,6 @@
 import { group, hardline, indent, line } from "../../document/index.js";
 import { hasComment } from "../utilities/comments.js";
+import { isForXStatementInitializer } from "../utilities/is-for-x-statement-initializer.js";
 import { printDeclareToken, printSemicolon } from "./miscellaneous.js";
 
 function printVariableDeclaration(path, options, print) {
@@ -9,11 +10,7 @@ function printVariableDeclaration(path, options, print) {
   // We generally want to terminate all variable declarations with a
   // semicolon, except when they in the () part of for loops.
 
-  const isForXStatementInitializer =
-    (path.key === "init" && path.parent.type === "ForStatement") ||
-    (path.key === "left" &&
-      (path.parent.type === "ForInStatement" ||
-        path.parent.type === "ForOfStatement"));
+  const isForXInitializer = isForXStatementInitializer(path);
 
   const hasValue = node.declarations.some((declarator) => declarator.init);
 
@@ -34,11 +31,11 @@ function printVariableDeclaration(path, options, print) {
         .slice(1)
         .map((doc) => [
           ",",
-          hasValue && !isForXStatementInitializer ? hardline : line,
+          hasValue && !isForXInitializer ? hardline : line,
           doc,
         ]),
     ),
-    isForXStatementInitializer ? "" : printSemicolon(options),
+    isForXInitializer ? "" : printSemicolon(options),
   ]);
 }
 

src/language-js/semicolon/should-ignored-node-print-semicolon.js

@@ -0,0 +1,42 @@
+import { shouldAddContentEnd } from "../location/index.js";
+import { isForXStatementInitializer } from "../utilities/is-for-x-statement-initializer.js";
+
+function shouldPrintSemicolon(node) {
+  if (shouldAddContentEnd(node) && node.__contentEnd) {
+    return true;
+  }
+
+  const { type } = node;
+
+  if (
+    type === "BreakStatement" ||
+    type === "ContinueStatement" ||
+    type === "DebuggerStatement" ||
+    type === "VariableDeclaration"
+  ) {
+    return true;
+  }
+
+  if (type === "IfStatement") {
+    return shouldPrintSemicolon(node.alternate ?? node.consequent);
+  }
+
+  if (
+    type === "ForInStatement" ||
+    type === "ForOfStatement" ||
+    type === "ForStatement" ||
+    type === "LabeledStatement" ||
+    type === "WithStatement" ||
+    type === "WhileStatement"
+  ) {
+    return shouldPrintSemicolon(node.body);
+  }
+
+  return false;
+}
+
+function shouldIgnoredNodePrintSemicolon(path) {
+  return !isForXStatementInitializer(path) && shouldPrintSemicolon(path.node);
+}
+
+export { shouldIgnoredNodePrintSemicolon };

src/language-js/utilities/is-for-x-statement-initializer.js

@@ -0,0 +1,9 @@
+function isForXStatementInitializer({ key, parent }) {
+  return (
+    (key === "init" && parent.type === "ForStatement") ||
+    (key === "left" &&
+      (parent.type === "ForInStatement" || parent.type === "ForOfStatement"))
+  );
+}
+
+export { isForXStatementInitializer };

tests/format/js/ignore/semi/__snapshots__/format.test.js.snap

@@ -209,6 +209,69 @@ function foo() {
 ================================================================================
 `;
 
+exports[`for-x-initializer.js - {"semi":false} format 1`] = `
+====================================options=====================================
+parsers: ["babel", "flow", "typescript"]
+semi: false
+                                                      printWidth: 80 (default) |
+=====================================input======================================
+for (/* prettier-ignore */ let i  = 0; i < 1; i++) {}
+for (/* prettier-ignore */ let  [a,b] in c) foo();
+for (/* prettier-ignore */ const  {a,b} of c) foo();
+for (
+  // prettier-ignore
+  let i  = 0, j  = 1;
+  i < 1;
+  i++
+) {}
+for (/* prettier-ignore */ i  = 0; i < 1; i++) {}
+
+=====================================output=====================================
+for (/* prettier-ignore */ let i  = 0; i < 1; i++) {}
+for (/* prettier-ignore */ let  [a,b] in c) foo()
+for (/* prettier-ignore */ const  {a,b} of c) foo()
+for (
+  // prettier-ignore
+  let i  = 0, j  = 1;
+  i < 1;
+  i++
+) {}
+for (/* prettier-ignore */ i  = 0; i < 1; i++) {}
+
+================================================================================
+`;
+
+exports[`for-x-initializer.js format 1`] = `
+====================================options=====================================
+parsers: ["babel", "flow", "typescript"]
+                                                      printWidth: 80 (default) |
+=====================================input======================================
+for (/* prettier-ignore */ let i  = 0; i < 1; i++) {}
+for (/* prettier-ignore */ let  [a,b] in c) foo();
+for (/* prettier-ignore */ const  {a,b} of c) foo();
+for (
+  // prettier-ignore
+  let i  = 0, j  = 1;
+  i < 1;
+  i++
+) {}
+for (/* prettier-ignore */ i  = 0; i < 1; i++) {}
+
+=====================================output=====================================
+for (/* prettier-ignore */ let i  = 0; i < 1; i++) {}
+for (/* prettier-ignore */ let  [a,b] in c) foo();
+for (/* prettier-ignore */ const  {a,b} of c) foo();
+for (
+  // prettier-ignore
+  let i  = 0, j  = 1;
+  i < 1;
+  i++
+) {}
+for (/* prettier-ignore */ i  = 0; i < 1; i++) {}
+
+================================================================================
+`;
+
 exports[`head-ignored.js - {"semi":false} format 1`] = `
 ====================================options=====================================
 parsers: ["babel", "flow", "typescript"]

tests/format/js/ignore/semi/for-x-initializer.js

@@ -0,0 +1,10 @@
+for (/* prettier-ignore */ let i  = 0; i < 1; i++) {}
+for (/* prettier-ignore */ let  [a,b] in c) foo();
+for (/* prettier-ignore */ const  {a,b} of c) foo();
+for (
+  // prettier-ignore
+  let i  = 0, j  = 1;
+  i < 1;
+  i++
+) {}
+for (/* prettier-ignore */ i  = 0; i < 1; i++) {}