feat: support non-js languages

.changeset/weak-lamps-refuse.md

@@ -0,0 +1,5 @@
+---
+"eslint-plugin-prettier": minor
+---
+
+feat: support non-js languages like `css` for `@eslint/css` and `json` for `@eslint/json`

eslint-plugin-prettier.js

@@ -7,6 +7,7 @@
 
 /**
  * @import {AST, ESLint, Linter, Rule, SourceCode} from 'eslint'
+ * @import {Position} from 'estree'
  * @import {FileInfoOptions, Options as PrettierOptions} from 'prettier'
  * @import {Difference} from 'prettier-linter-helpers'
  */
@@ -57,6 +58,42 @@ let prettierFormat;
 //  Rule Definition
 // ------------------------------------------------------------------------------
 
+/** @type {WeakMap<SourceCode, number[]>} */
+const lineIndexesCache = new WeakMap();
+
+/**
+ * Ponyfill `sourceCode.getLocFromIndex` when it's unavailable.
+ *
+ * See also `getLocFromIndex` in `@eslint/js`.
+ *
+ * @param {SourceCode} sourceCode
+ * @param {number} index
+ * @returns {Position}
+ */
+function getLocFromIndex(sourceCode, index) {
+  if (typeof sourceCode.getLocFromIndex === 'function') {
+    return sourceCode.getLocFromIndex(index);
+  }
+
+  let lineIndexes = lineIndexesCache.get(sourceCode);
+  if (!lineIndexes) {
+    lineIndexes = [...sourceCode.text.matchAll(/\r?\n/g)].map(
+      match => match.index,
+    );
+    // first line in the file starts at byte offset 0
+    lineIndexes.unshift(0);
+    lineIndexesCache.set(sourceCode, lineIndexes);
+  }
+
+  let line = 0;
+  while (line + 1 < lineIndexes.length && lineIndexes[line + 1] < index) {
+    line += 1;
+  }
+  const column = index - lineIndexes[line];
+
+  return { line: line + 1, column };
+}
+
 /**
  * Reports a difference.
  *
@@ -71,9 +108,9 @@ function reportDifference(context, difference) {
   // `context.getSourceCode()` was deprecated in ESLint v8.40.0 and replaced
   // with the `sourceCode` property.
   // TODO: Only use property when our eslint peerDependency is >=8.40.0.
-  const [start, end] = range.map(index =>
-    (context.sourceCode ?? context.getSourceCode()).getLocFromIndex(index),
-  );
+  const sourceCode = context.sourceCode ?? context.getSourceCode();
+
+  const [start, end] = range.map(index => getLocFromIndex(sourceCode, index));
 
   context.report({
     messageId: operation,
@@ -168,7 +205,8 @@ const eslintPluginPrettier = {
         const source = sourceCode.text;
 
         return {
-          Program(node) {
+          /** @param {unknown} node */
+          [sourceCode.ast.type](node) {
             if (!prettierFormat) {
               // Prettier is expensive to load, so only load it if needed.
               prettierFormat = /** @type {PrettierFormat} */ (

package.json

@@ -74,6 +74,7 @@
     "@commitlint/config-conventional": "^19.8.0",
     "@eslint-community/eslint-plugin-eslint-comments": "^4.4.1",
     "@eslint/js": "^9.23.0",
+    "@eslint/json": "^0.12.0",
     "@graphql-eslint/eslint-plugin": "^4.3.0",
     "@html-eslint/parser": "^0.41.0",
     "@prettier/plugin-pug": "^3.2.1",

test/fixtures/empty.json

@@ -0,0 +1 @@
+

test/invalid/json.txt

@@ -0,0 +1,22 @@
+CODE:
+{
+"a": [
+"b",
+{"c":
+"d"}
+] }
+
+OUTPUT:
+{
+  "a": ["b", { "c": "d" }]
+}
+
+OPTIONS:
+[]
+
+ERRORS:
+[
+  {
+    message: 'Replace `"a":·[⏎"b",⏎{"c":⏎"d"}⏎]·` with `··"a":·["b",·{·"c":·"d"·}]⏎`',
+  },
+]

test/prettier.mjs

@@ -25,12 +25,15 @@ import eslintPluginPug from 'eslint-plugin-pug';
 import vueEslintParser from 'vue-eslint-parser';
 import * as eslintPluginGraphql from '@graphql-eslint/eslint-plugin';
 import eslintMdx from 'eslint-mdx';
+import eslintPluginJson from '@eslint/json';
 
 const rule = eslintPluginPrettier.rules.prettier;
 const RuleTester =
   eslintUnsupportedApi.FlatRuleTester ?? eslintPackage.RuleTester;
 const ESLint = eslintUnsupportedApi.FlatESLint ?? eslintPackage.ESLint;
 
+const isESLint9 = !eslintUnsupportedApi.FlatRuleTester;
+
 // ------------------------------------------------------------------------------
 // Tests
 // ------------------------------------------------------------------------------
@@ -380,6 +383,53 @@ runFixture('invalid-prettierrc/*', [
   ],
 ]);
 
+runFixture('*.json', [
+  [
+    {
+      column: 1,
+      endColumn: 1,
+      endLine: 2,
+      fix: {
+        range: [0, 1],
+        text: '',
+      },
+      line: 1,
+      message: 'Delete `⏎`',
+      messageId: 'delete',
+      nodeType: null,
+      ruleId: 'prettier/prettier',
+      severity: 2,
+    },
+  ],
+]);
+
+if (isESLint9) {
+  const jsonRuleTester = new RuleTester({
+    plugins: {
+      json: eslintPluginJson,
+    },
+    language: 'json/json',
+  });
+
+  jsonRuleTester.run('@eslint/json', rule, {
+    valid: [
+      {
+        code: '{}\n',
+        filename: 'empty.json',
+      },
+      {
+        code: '{ "foo": 1 }\n',
+        filename: 'simple.json',
+      },
+    ],
+    invalid: [
+      Object.assign(loadInvalidFixture('json'), {
+        filename: 'invalid.json',
+      }),
+    ],
+  });
+}
+
 // ------------------------------------------------------------------------------
 //  Helpers
 // ------------------------------------------------------------------------------
@@ -436,7 +486,7 @@ function getPrettierRcJsFilename(dir, file = 'dummy.js') {
  * @type {ESLint}
  * @import {ESLint} from 'eslint'
  */
-let eslint;
+var eslint; // bad mocha: `ReferenceError: Cannot access 'eslint' before initialization`
 
 /**
  * @param {string} pattern
@@ -504,11 +554,16 @@ async function runFixture(pattern, asserts, skip) {
             pug: eslintPluginPug,
           },
         },
+        {
+          files: ['**/*.json'],
+          plugins: {
+            json: eslintPluginJson,
+          },
+        },
       ],
       ignore: false,
     });
   }
-
   if (skip) {
     return;
   }