Add index to FastPath#each() callback (#9499)

Co-authored-by: Georgii Dolzhykov <thorn.mailbox@gmail.com>

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

@@ -2,7 +2,8 @@
 
 module.exports = {
   rules: {
-    "require-json-extensions": require("./require-json-extensions"),
     "better-parent-property-check-in-needs-parens": require("./better-parent-property-check-in-needs-parens"),
+    "prefer-fast-path-each": require("./prefer-fast-path-each"),
+    "require-json-extensions": require("./require-json-extensions"),
   },
 };

scripts/tools/eslint-plugin-prettier-internal-rules/prefer-fast-path-each.js

@@ -0,0 +1,42 @@
+"use strict";
+
+const selector = [
+  "ExpressionStatement",
+  ">",
+  "CallExpression.expression",
+  "[optional=false]",
+  ">",
+  "MemberExpression.callee",
+  "[computed=false]",
+  "[optional=false]",
+  ">",
+  "Identifier.property",
+  '[name="map"]',
+].join("");
+
+const messageId = "prefer-fast-path-each";
+
+module.exports = {
+  meta: {
+    type: "suggestion",
+    docs: {
+      url:
+        "https://github.com/prettier/prettier/blob/master/scripts/eslint-plugin-prettier-internal-rules/require-json-extensions.js",
+    },
+    messages: {
+      [messageId]: "Prefer `FastPath#each()` over `FastPath#map()`.",
+    },
+    fixable: "code",
+  },
+  create(context) {
+    return {
+      [selector](node) {
+        context.report({
+          node,
+          messageId,
+          fix: (fixer) => fixer.replaceText(node, "each"),
+        });
+      },
+    };
+  },
+};