style: Add new ESLint rule no-empty-string-for-ifbreak (#10172)

* Add new ESLint rule for ifBreak

* Fix for third argument

* Run fix with new rule

* Address review

* Fix

* Update no-empty-flat-contents-for-if-break.js

* Fix CI config

Co-authored-by: fisker Cheung <lionkay@gmail.com>

scripts/tools/eslint-plugin-prettier-internal-rules/index.js

@@ -10,5 +10,6 @@ module.exports = {
     "prefer-fast-path-each": require("./prefer-fast-path-each"),
     "prefer-is-non-empty-array": require("./prefer-is-non-empty-array"),
     "require-json-extensions": require("./require-json-extensions"),
+    "no-empty-flat-contents-for-if-break": require("./no-empty-flat-contents-for-if-break"),
   },
 };

scripts/tools/eslint-plugin-prettier-internal-rules/no-empty-flat-contents-for-if-break.js

@@ -0,0 +1,42 @@
+"use strict";
+
+const selector = [
+  "CallExpression",
+  "[optional=false]",
+  '[callee.type="Identifier"]',
+  '[callee.name="ifBreak"]',
+  "[arguments.length=2]",
+  '[arguments.1.type="Literal"]',
+  '[arguments.1.value=""]',
+  ':not([arguments.0.type="SpreadElement"])',
+].join("");
+
+const messageId = "no-empty-flat-contents-for-if-break";
+
+module.exports = {
+  meta: {
+    type: "suggestion",
+    docs: {
+      url:
+        "https://github.com/prettier/prettier/blob/main/scripts/eslint-plugin-prettier-internal-rules/no-empty-flat-contents-for-if-break.js",
+    },
+    messages: {
+      [messageId]:
+        "Please don't pass an empty string to second parameter of ifBreak.",
+    },
+    fixable: "code",
+  },
+  create(context) {
+    return {
+      [selector](node) {
+        const [breakContents] = node.arguments;
+        context.report({
+          node,
+          messageId,
+          fix: (fixer) =>
+            fixer.removeRange([breakContents.range[1], node.range[1] - 1]),
+        });
+      },
+    };
+  },
+};

scripts/tools/eslint-plugin-prettier-internal-rules/test.js

@@ -204,3 +204,46 @@ test("require-json-extensions", {
     },
   ],
 });
+
+test("no-empty-flat-contents-for-if-break", {
+  valid: [
+    "ifBreak('foo', 'bar')",
+    "ifBreak(doc1, doc2)",
+    "ifBreak(',')",
+    "ifBreak(doc)",
+    "ifBreak('foo', '', { groupId })",
+    "ifBreak(...foo, { groupId })",
+  ],
+  invalid: [
+    {
+      code: "ifBreak('foo', '')",
+      output: "ifBreak('foo')",
+      errors: [
+        {
+          message:
+            "Please don't pass an empty string to second parameter of ifBreak.",
+        },
+      ],
+    },
+    {
+      code: "ifBreak('foo'    ,     ''   )",
+      output: "ifBreak('foo')",
+      errors: [
+        {
+          message:
+            "Please don't pass an empty string to second parameter of ifBreak.",
+        },
+      ],
+    },
+    {
+      code: "ifBreak(doc, '')",
+      output: "ifBreak(doc)",
+      errors: [
+        {
+          message:
+            "Please don't pass an empty string to second parameter of ifBreak.",
+        },
+      ],
+    },
+  ],
+});