feat: support eslint v8

Author: SimenB

.github/workflows/nodejs.yml

@@ -19,13 +19,17 @@ jobs:
       fail-fast: false
       matrix:
         node-version: [10.x, 12.x, 14.x, 16.x]
-        eslint-version: [6, 7]
+        eslint-version: [6, 7, '^8.0.0-0']
         jest-version: [25, 26, 27]
         include:
           # eslint@7 and jest@26 doesn't support node@8
           - node-version: 8.x
             eslint-version: 6
             jest-version: 25
+        exclude:
+          # eslint@8 doesn't support node@10
+          - node-version: 10.x
+            eslint-version: '^8.0.0-0'
     runs-on: ubuntu-latest
 
     steps:

integrationTests/custom-parser.test.js

@@ -1,14 +1,11 @@
-const eslint = require('eslint');
 const runJest = require('./runJest');
+const { version } = require('../src/utils/eslintVersion');
 
 // Note: ESLint versions <6 have a different error message for this test. The
 // snapshot file contains both messages so we can test across both versions.
 // Without the skipped tests for the "other" version, the tests will always fail
 // with `1 snapshot obsolete`.
-if (
-  eslint.CLIEngine.version.startsWith('4') ||
-  eslint.CLIEngine.version.startsWith('5')
-) {
+if (version.startsWith('4') || version.startsWith('5')) {
   it.skip("Doesn't override parser when not set", () => {});
   it("Doesn't override parser when not set [ESLint<6]", () => {
     return expect(runJest('custom-parser')).resolves.toMatchSnapshot();

package.json

@@ -33,7 +33,7 @@
     "@babel/core": "^7.10.4",
     "@babel/preset-env": "^7.10.4",
     "babel-jest": "^25.1 || ^26 || ^27",
-    "eslint": "^6 || ^7",
+    "eslint": "^6 || ^7 || ^8.0.0-0",
     "eslint-config-airbnb-base": "^14.2.0",
     "eslint-config-prettier": "^6.11.0",
     "eslint-plugin-import": "^2.22.0",
@@ -47,7 +47,7 @@
     "rimraf": "^3.0.2"
   },
   "peerDependencies": {
-    "eslint": "^6 || ^7",
+    "eslint": "^6 || ^7 || ^8.0.0-0",
     "jest": "^25.1 || ^26 || ^27"
   },
   "prettier": {

src/runner/__tests__/runESLint.test.js

@@ -25,7 +25,7 @@ const runESLintRunnerWithMockedEngine = options => {
   return runESLint({ extraOptions: {}, ...options.runESLint });
 };
 
-it('Requires the config setupTestFrameworkScriptFile when specified', () => {
+it('Requires the config setupTestFrameworkScriptFile when specified', async () => {
   const setupFile = path.join(__dirname, './path/to/setupFile.js');
 
   let setupFileWasLoaded = false;
@@ -37,7 +37,7 @@ it('Requires the config setupTestFrameworkScriptFile when specified', () => {
     { virtual: true },
   );
 
-  runESLintRunnerWithMockedEngine({
+  await runESLintRunnerWithMockedEngine({
     cliEngine: {
       ignoredFiles: ['/path/to/file.test.js'],
       errorCount: 0,
@@ -53,8 +53,8 @@ it('Requires the config setupTestFrameworkScriptFile when specified', () => {
   expect(setupFileWasLoaded).toBeTruthy();
 });
 
-it('Returns "skipped" when the test path is ignored', () => {
-  const result = runESLintRunnerWithMockedEngine({
+it('Returns "skipped" when the test path is ignored', async () => {
+  const result = await runESLintRunnerWithMockedEngine({
     cliEngine: {
       ignoredFiles: ['/path/to/file.test.js'],
       errorCount: 0,
@@ -73,8 +73,8 @@ it('Returns "skipped" when the test path is ignored', () => {
   });
 });
 
-it('Returns "passed" when the test passed', () => {
-  const result = runESLintRunnerWithMockedEngine({
+it('Returns "passed" when the test passed', async () => {
+  const result = await runESLintRunnerWithMockedEngine({
     cliEngine: {
       ignoredFiles: [],
       errorCount: 0,
@@ -92,8 +92,8 @@ it('Returns "passed" when the test passed', () => {
   });
 });
 
-it('Returns "fail" when the test failed', () => {
-  const result = runESLintRunnerWithMockedEngine({
+it('Returns "fail" when the test failed', async () => {
+  const result = await runESLintRunnerWithMockedEngine({
     cliEngine: {
       ignoredFiles: [],
       errorCount: 1,

src/runner/runESLint.js

@@ -1,5 +1,5 @@
 const { pass, fail, skip } = require('create-jest-runner');
-const { CLIEngine } = require('eslint');
+const { CLIEngine, ESLint } = require('eslint');
 const getESLintOptions = require('../utils/getESLintOptions');
 
 const getComputedFixValue = ({ fix, quiet, fixDryRun }) => {
@@ -9,50 +9,61 @@ const getComputedFixValue = ({ fix, quiet, fixDryRun }) => {
   return undefined;
 };
 
+const ESLintEngine = ESLint || CLIEngine;
+
 let cachedValues;
 const getCachedValues = (config, extraOptions) => {
   if (!cachedValues) {
+    const useEngine = ESLint == null;
     const { cliOptions: baseCliOptions } = getESLintOptions(config);
     const cliOptions = {
       ...baseCliOptions,
       fix: getComputedFixValue(baseCliOptions),
       ...extraOptions,
     };
-    const cli = new CLIEngine(cliOptions);
+    const cli = useEngine ? new CLIEngine(cliOptions) : new ESLint(cliOptions);
     const formatter = cli.getFormatter(cliOptions.format);
 
-    cachedValues = { cli, formatter, cliOptions };
+    cachedValues = {
+      isPathIgnored: cli.isPathIgnored,
+      lintFiles: cli.lintFiles || cli.executeOnFiles,
+      formatter,
+      cliOptions,
+    };
   }
 
   return cachedValues;
 };
 
-const runESLint = ({ testPath, config, extraOptions }) => {
+const runESLint = async ({ testPath, config, extraOptions }) => {
   const start = Date.now();
 
   if (config.setupTestFrameworkScriptFile) {
     // eslint-disable-next-line import/no-dynamic-require,global-require
     require(config.setupTestFrameworkScriptFile);
   }
 
-  const { cli, formatter, cliOptions } = getCachedValues(config, extraOptions);
+  const { isPathIgnored, lintFiles, formatter, cliOptions } = getCachedValues(
+    config,
+    extraOptions,
+  );
 
-  if (cli.isPathIgnored(testPath)) {
+  if (isPathIgnored(testPath)) {
     const end = Date.now();
     return skip({ start, end, test: { path: testPath, title: 'ESLint' } });
   }
 
-  const report = cli.executeOnFiles([testPath]);
+  const report = await lintFiles([testPath]);
 
   if (cliOptions.fix && !cliOptions.fixDryRun) {
-    CLIEngine.outputFixes(report);
+    await ESLintEngine.outputFixes(report);
   }
 
   const end = Date.now();
 
   const message = formatter(
     cliOptions.quiet
-      ? CLIEngine.getErrorResults(report.results)
+      ? ESLintEngine.getErrorResults(report.results)
       : report.results,
   );
 

src/utils/eslintVersion.js

@@ -0,0 +1,6 @@
+'use strict';
+
+const version = require('eslint/package.json').version
+
+module.exports.version = version;
+module.exports.isV8 = version.startsWith('8')

yarn.lock

@@ -2213,7 +2213,7 @@ eslint-visitor-keys@^2.0.0:
   resolved "https://registry.yarnpkg.com/eslint-visitor-keys/-/eslint-visitor-keys-2.1.0.tgz#f65328259305927392c938ed44eb0a5c9b2bd303"
   integrity sha512-0rSmRBzXgDzIsD6mGdJgevzgezI534Cer5L/vyMX0kHzT/jiB43jRhd9YUlMGYLQy2zprNmoT8qasCGtY+QaKw==
 
-"eslint@^6 || ^7":
+"eslint@^6 || ^7 || ^8.0.0-0":
   version "7.28.0"
   resolved "https://registry.yarnpkg.com/eslint/-/eslint-7.28.0.tgz#435aa17a0b82c13bb2be9d51408b617e49c1e820"
   integrity sha512-UMfH0VSjP0G4p3EWirscJEQ/cHqnT/iuH6oNZOB94nBjWbMnhGEPxsZm1eyIW0C/9jLI0Fow4W5DXLjEI7mn1g==