Prettier v3 (#305)

Minimum supported Prettier version is v3.0.0
Minimum supported stylelint version is 15.8.0

- Use `await import()` instead of require.
- Use async (and now the only) versions of resolveConfig, getFileInfo
  and format
- Tweak jest/eslint configs to account for prettier using esmodules
- Ignore testing svelte files as prettier-plugin-svelte doesn't yet have
  a release that supports prettier v3

.eslintrc.js

@@ -4,9 +4,14 @@ module.exports = {
   plugins: ['node'],
   extends: ['plugin:node/recommended', 'plugin:prettier/recommended'],
   env: {node: true, jest: true},
+  parserOptions: {ecmaVersion: '2020'},
   root: true,
   rules: {
     'node/no-unpublished-require': ['error', {allowModules: ['stylelint']}],
     'node/no-missing-require': ['error', {allowModules: ['styled-components']}],
+    'node/no-unsupported-features/es-syntax': [
+      'error',
+      {ignores: ['dynamicImport']},
+    ],
   },
 };

.github/workflows/ci.yml

@@ -12,7 +12,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        stylelint-version: [14.x, 15.x]
+        stylelint-version: [15.x]
         node-version: [18.x, 16.x, 14.x]
 
     steps:

package.json

@@ -17,7 +17,7 @@
   "main": "stylelint-prettier.js",
   "scripts": {
     "lint": "eslint .",
-    "test": "yarn run lint && jest",
+    "test": "yarn run lint && node --experimental-vm-modules node_modules/jest/bin/jest.js",
     "format": "yarn run prettier '**/*.{js,json,md}' --write && yarn run lint --fix"
   },
   "repository": {
@@ -32,26 +32,26 @@
     "prettier-linter-helpers": "^1.0.0"
   },
   "peerDependencies": {
-    "prettier": ">=2.0.0",
-    "stylelint": ">=14.0.0"
+    "prettier": ">=3.0.0",
+    "stylelint": ">=15.8.0"
   },
   "devDependencies": {
     "eslint": "^8.34.0",
     "eslint-config-prettier": "^8.6.0",
     "eslint-plugin-node": "^11.1.0",
-    "eslint-plugin-prettier": "^4.2.1",
-    "jest": "^29.4.3",
+    "eslint-plugin-prettier": "^5.0.0-alpha.2",
+    "jest": "^29.6.1",
     "jest-preset-stylelint": "^6.1.0",
     "postcss": "^8.4.21",
     "postcss-html": "^1.5.0",
     "postcss-markdown": "^1.2.0",
     "postcss-scss": "^4.0.6",
     "postcss-styled-syntax": "^0.3.3",
     "postcss-syntax": "^0.36.2",
-    "prettier": "^2.8.4",
+    "prettier": "^3.0.0",
     "prettier-plugin-svelte": "^2.9.0",
     "strip-ansi": "^6.0.0",
-    "stylelint": "^15.0.0",
+    "stylelint": "^15.8.0",
     "svelte": "^3.55.0",
     "typescript": "4.9.5"
   },
@@ -60,9 +60,10 @@
   },
   "jest": {
     "preset": "jest-preset-stylelint",
+    "transform": {},
     "setupFiles": [
       "./jest-setup.js"
     ]
   },
   "license": "MIT"
-}
+}

stylelint-prettier.js

@@ -4,6 +4,8 @@ const {
   generateDifferences,
 } = require('prettier-linter-helpers');
 
+const prettierPromise = import('prettier');
+
 const {INSERT, DELETE, REPLACE} = generateDifferences;
 
 let prettier;
@@ -21,7 +23,7 @@ const messages = stylelint.utils.ruleMessages(ruleName, {
 module.exports = stylelint.createPlugin(
   ruleName,
   (expectation, options, context) => {
-    return (root, result) => {
+    return async (root, result) => {
       const validOptions = stylelint.utils.validateOptions(result, ruleName, {
         actual: expectation,
       });
@@ -39,19 +41,19 @@ module.exports = stylelint.createPlugin(
 
       if (!prettier) {
         // Prettier is expensive to load, so only load it if needed.
-        prettier = require('prettier');
+        prettier = await prettierPromise;
       }
 
       // Default to '<input>' if a filepath was not provided.
       // This mimics eslint's behaviour
       const filepath = root.source.input.file || '<input>';
       const source = root.source.input.css;
 
-      const prettierRcOptions = prettier.resolveConfig.sync(filepath, {
+      const prettierRcOptions = await prettier.resolveConfig(filepath, {
         editorconfig: true,
       });
 
-      const prettierFileInfo = prettier.getFileInfo.sync(filepath, {
+      const prettierFileInfo = await prettier.getFileInfo(filepath, {
         resolveConfig: true,
         ignorePath: '.prettierignore',
       });
@@ -104,7 +106,7 @@ module.exports = stylelint.createPlugin(
         {filepath}
       );
       try {
-        prettierSource = prettier.format(source, prettierOptions);
+        prettierSource = await prettier.format(source, prettierOptions);
       } catch (err) {
         if (!(err instanceof SyntaxError)) {
           throw err;

test/stylelint-prettier-e2e.test.js

@@ -45,7 +45,10 @@ check.invalid.scss
    * files
    */
   test('HTML/Markdown/Vue/Svelte files', () => {
-    const result = runStylelint('*.{html,md,vue,svelte}');
+    // Once prettier-plugin-svelte is updated to support Prettier v3
+    // bring back testing against svelte files
+    // const result = runStylelint('*.{html,md,vue,svelte}');
+    const result = runStylelint('*.{html,md,vue}');
 
     const expectedResult = ``;