feat: use ESLint instead of CLIEngine when available (#128)

BREAKING CHANGE: Using `ESLint` might need different configuration
options. See eslint.org/docs/developer-guide/nodejs-api#parameters

.eslintrc.json

@@ -1,6 +1,9 @@
 {
   "extends": ["airbnb-base", "prettier"],
   "plugins": ["prettier", "jest"],
+  "parserOptions": {
+    "ecmaVersion": 11
+  },
   "rules": {
     "no-underscore-dangle": 0,
     "arrow-body-style": 0,

integrationTests/__fixtures__/passing/jest-runner-eslint.config.js

@@ -1,5 +1,8 @@
+const { ESLint } = require('eslint');
+
 module.exports = {
   cliOptions: {
-    global: ['hello'],
+    // `ESLint` requires this to be an object, not an array
+    global: ESLint ? { hello: true } : ['hello'],
   },
 };

package.json

@@ -26,7 +26,8 @@
   "dependencies": {
     "chalk": "^3.0.0",
     "cosmiconfig": "^6.0.0",
-    "create-jest-runner": "^0.6.0"
+    "create-jest-runner": "^0.6.0",
+    "dot-prop": "^5.3.0"
   },
   "devDependencies": {
     "@babel/cli": "^7.10.4",

src/runner/__tests__/runESLint.test.js

@@ -11,7 +11,12 @@ const runESLintRunnerWithMockedEngine = options => {
 
       executeOnFiles() {
         return {
+          results:
+            options.cliEngine.errorCount > 0
+              ? [{ errorCount: options.cliEngine.errorCount, warningCount: 0 }]
+              : [],
           errorCount: options.cliEngine.errorCount,
+          warningCount: 0,
         };
       }
 
@@ -25,7 +30,7 @@ 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 +42,7 @@ it('Requires the config setupTestFrameworkScriptFile when specified', () => {
     { virtual: true },
   );
 
-  runESLintRunnerWithMockedEngine({
+  await runESLintRunnerWithMockedEngine({
     cliEngine: {
       ignoredFiles: ['/path/to/file.test.js'],
       errorCount: 0,
@@ -53,8 +58,8 @@ 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 +78,8 @@ 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 +97,8 @@ 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 }) => {
@@ -9,54 +9,89 @@ const getComputedFixValue = ({ fix, quiet, fixDryRun }) => {
   return undefined;
 };
 
+const ESLintEngine = ESLint || CLIEngine;
+
 let cachedValues;
 const getCachedValues = (config, extraOptions) => {
   if (!cachedValues) {
-    const { cliOptions: baseCliOptions } = getESLintOptions(config);
+    const useEngine = ESLint == null;
+    const { cliOptions: baseCliOptions } = getESLintOptions(config, !useEngine);
     const cliOptions = {
       ...baseCliOptions,
       fix: getComputedFixValue(baseCliOptions),
       ...extraOptions,
     };
-    const cli = new CLIEngine(cliOptions);
-    const formatter = cli.getFormatter(cliOptions.format);
 
-    cachedValues = { cli, formatter, cliOptions };
+    // these are not constructor args, so remove them
+    const { fixDryRun, format, maxWarnings, quiet } = cliOptions;
+    delete cliOptions.fixDryRun;
+    delete cliOptions.format;
+    delete cliOptions.maxWarnings;
+    delete cliOptions.quiet;
+
+    const cli = useEngine ? new CLIEngine(cliOptions) : new ESLint(cliOptions);
+
+    cachedValues = {
+      isPathIgnored: cli.isPathIgnored.bind(cli),
+      lintFiles: (...args) => {
+        if (useEngine) {
+          return cli.executeOnFiles(...args).results;
+        }
+
+        return cli.lintFiles(...args);
+      },
+      formatter: async (...args) => {
+        if (useEngine) {
+          return cli.getFormatter(format)(...args);
+        }
+
+        const formatter = await cli.loadFormatter(format);
+
+        return formatter.format(...args);
+      },
+      cliOptions: {
+        ...cliOptions,
+        fixDryRun,
+        maxWarnings,
+        quiet,
+      },
+    };
   }
 
   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 (await 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)
-      : report.results,
+  const message = await formatter(
+    cliOptions.quiet ? ESLintEngine.getErrorResults(report) : report,
   );
 
-  if (report.errorCount > 0) {
+  if (report[0]?.errorCount > 0) {
     return fail({
       start,
       end,
@@ -65,7 +100,8 @@ const runESLint = ({ testPath, config, extraOptions }) => {
   }
 
   const tooManyWarnings =
-    cliOptions.maxWarnings >= 0 && report.warningCount > cliOptions.maxWarnings;
+    cliOptions.maxWarnings >= 0 &&
+    report[0]?.warningCount > cliOptions.maxWarnings;
   if (tooManyWarnings) {
     return fail({
       start,
@@ -84,7 +120,7 @@ const runESLint = ({ testPath, config, extraOptions }) => {
     test: { path: testPath, title: 'ESLint' },
   });
 
-  if (!cliOptions.quiet && report.warningCount > 0) {
+  if (!cliOptions.quiet && report[0]?.warningCount > 0) {
     result.console = [{ message, origin: '', type: 'warn' }];
   }
 

src/utils/__tests__/normalizeConfig.test.js

@@ -3,7 +3,7 @@ const normalizeConfig = require('../normalizeConfig');
 const normalizeCLIOptions = cliOptions =>
   normalizeConfig({ cliOptions }).cliOptions;
 
-it('ignores unkown options', () => {
+it('ignores unknown options', () => {
   expect(normalizeCLIOptions({ other: true })).not.toMatchObject({
     other: true,
   });

src/utils/getESLintOptions.js

@@ -3,14 +3,14 @@ const normalizeConfig = require('./normalizeConfig');
 
 const explorer = cosmiconfigSync('jest-runner-eslint');
 
-const getESLintOptions = config => {
+const getESLintOptions = (config, newApi) => {
   const result = explorer.search(config.rootDir);
 
   if (result) {
-    return normalizeConfig(result.config);
+    return normalizeConfig(result.config, newApi);
   }
 
-  return normalizeConfig({});
+  return normalizeConfig({}, newApi);
 };
 
 module.exports = getESLintOptions;

src/utils/normalizeConfig.js

@@ -1,3 +1,5 @@
+const dotProp = require('dot-prop');
+
 const identity = v => v;
 const negate = v => !v;
 const asArray = v => (typeof v === 'string' ? [v] : v);
@@ -12,7 +14,7 @@ const asInt = v => {
   return int;
 };
 
-const BASE_CONFIG = {
+const OLD_BASE_CONFIG = {
   cache: {
     default: false,
   },
@@ -40,7 +42,7 @@ const BASE_CONFIG = {
     default: false,
   },
   format: {
-    default: null,
+    default: undefined,
   },
   global: {
     name: 'globals',
@@ -103,28 +105,70 @@ const BASE_CONFIG = {
   },
 };
 
+const BASE_CONFIG = {
+  ...OLD_BASE_CONFIG,
+  config: {
+    name: 'overrideConfigFile',
+    default: null,
+  },
+  env: {
+    name: 'overrideConfig.env',
+    default: {},
+  },
+  global: {
+    name: 'overrideConfig.globals',
+    default: {},
+  },
+  ignorePattern: {
+    name: 'overrideConfig.ignorePatterns',
+    default: [],
+    transform: asArray,
+  },
+  parser: {
+    name: 'overrideConfig.parser',
+    default: null,
+  },
+  parserOptions: {
+    name: 'overrideConfig.parserOptions',
+    default: {},
+  },
+  plugin: {
+    name: 'overrideConfig.plugins',
+    default: [],
+    transform: asArray,
+  },
+  reportUnusedDisableDirectives: {
+    default: null,
+  },
+  rules: {
+    name: 'overrideConfig.rules',
+    default: {},
+  },
+};
+
 /* eslint-disable no-param-reassign */
-const normalizeCliOptions = rawConfig =>
-  Object.keys(BASE_CONFIG).reduce((config, key) => {
+const normalizeCliOptions = (rawConfig, newApi) => {
+  const configToUse = newApi ? BASE_CONFIG : OLD_BASE_CONFIG;
+  return Object.keys(configToUse).reduce((config, key) => {
     const {
       name = key,
       transform = identity,
       default: defaultValue,
-    } = BASE_CONFIG[key];
+    } = configToUse[key];
 
     const value = rawConfig[key] !== undefined ? rawConfig[key] : defaultValue;
 
-    return {
-      ...config,
-      [name]: transform(value),
-    };
+    dotProp.set(config, name, transform(value));
+
+    return config;
   }, {});
+};
 /* eslint-enable no-param-reassign */
 
-const normalizeConfig = config => {
+const normalizeConfig = (config, newApi) => {
   return {
     ...config,
-    cliOptions: normalizeCliOptions(config.cliOptions || {}),
+    cliOptions: normalizeCliOptions(config.cliOptions || {}, newApi),
   };
 };
 

yarn.lock

@@ -2036,6 +2036,13 @@ domexception@^2.0.1:
   dependencies:
     webidl-conversions "^5.0.0"
 
+dot-prop@^5.3.0:
+  version "5.3.0"
+  resolved "https://registry.yarnpkg.com/dot-prop/-/dot-prop-5.3.0.tgz#90ccce708cd9cd82cc4dc8c3ddd9abdd55b20e88"
+  integrity sha512-QM8q3zDe58hqUqjraQOmzZ1LIH9SWQJTlEKCH4kJ2oQvLZk7RbQXvtDM2XEq3fwkV9CCvvH4LA0AV+ogFsBM2Q==
+  dependencies:
+    is-obj "^2.0.0"
+
 electron-to-chromium@^1.3.830:
   version "1.3.842"
   resolved "https://registry.yarnpkg.com/electron-to-chromium/-/electron-to-chromium-1.3.842.tgz#641e414012dded277468892c0156cb01984f4f6f"
@@ -2956,6 +2963,11 @@ is-number@^7.0.0:
   resolved "https://registry.yarnpkg.com/is-number/-/is-number-7.0.0.tgz#7535345b896734d5f80c4d06c50955527a14f12b"
   integrity sha512-41Cifkg6e8TylSpdtTpeLVMqvSBEVzTttHvERD741+pnZ8ANv0004MRL43QKPDlK9cGvNp6NZWZUBlbGXYxxng==
 
+is-obj@^2.0.0:
+  version "2.0.0"
+  resolved "https://registry.yarnpkg.com/is-obj/-/is-obj-2.0.0.tgz#473fb05d973705e3fd9620545018ca8e22ef4982"
+  integrity sha512-drqDG3cbczxxEJRoOXcOjtdp1J/lyp1mNn0xaznRs8+muBhgQcrnbspox5X5fOw0HnMnbfDzvnEMEtqDEJEo8w==
+
 is-plain-object@^2.0.3, is-plain-object@^2.0.4:
   version "2.0.4"
   resolved "https://registry.yarnpkg.com/is-plain-object/-/is-plain-object-2.0.4.tgz#2c163b3fafb1b606d9d17928f05c2a1c38e07677"