tests(lint): require file extension in require() (#9017)

.eslintrc.js

@@ -9,6 +9,7 @@ module.exports = {
   // start with google standard style
   //     https://github.com/google/eslint-config-google/blob/master/index.js
   extends: ['eslint:recommended', 'google'],
+  plugins: ['eslint-plugin-local-rules'], // include custom rules
   env: {
     node: true,
     es6: true,
@@ -64,6 +65,9 @@ module.exports = {
       functions: 'never',
     }],
 
+    // Custom lighthouse rules
+    'local-rules/require-file-extension': 2,
+
     // Disabled rules
     'require-jsdoc': 0,
     'valid-jsdoc': 0,

clients/extension/scripts/extension-entry.js

@@ -5,12 +5,12 @@
  */
 'use strict';
 
-const lighthouse = require('../../../lighthouse-core/index');
-const Config = require('../../../lighthouse-core/config/config');
+const lighthouse = require('../../../lighthouse-core/index.js');
+const Config = require('../../../lighthouse-core/config/config.js');
 const defaultConfig = require('../../../lighthouse-core/config/default-config.js');
 const i18n = require('../../../lighthouse-core/lib/i18n/i18n.js');
 
-const ExtensionProtocol = require('../../../lighthouse-core/gather/connections/extension');
+const ExtensionProtocol = require('../../../lighthouse-core/gather/connections/extension.js');
 const log = require('lighthouse-logger');
 
 /** @typedef {import('../../../lighthouse-core/gather/connections/connection.js')} Connection */

eslint-local-rules.js

@@ -0,0 +1,106 @@
+/**
+ * @license Copyright 2019 Google Inc. All Rights Reserved.
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at http://www.apache.org/licenses/LICENSE-2.0
+ * Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.
+ */
+'use strict';
+
+/**
+ * @fileoverview A collection of eslint rules written specifically for
+ * Lighthouse. These are included by the eslint-plugin-local-rules plugin.
+ */
+
+const path = require('path');
+
+/** @typedef {import('eslint').Rule.RuleModule} RuleModule */
+
+/**
+ * Use `require.resolve()` to resolve the location of `path` from a location of
+ * `baseDir` and return it. Returns null if unable to resolve a path.
+ * @param {string} path
+ * @param {string} baseDir
+ * @return {string|null}
+ */
+function requireResolveOrNull(path, baseDir) {
+  try {
+    return require.resolve(path, {
+      paths: [baseDir],
+    });
+  } catch (err) {
+    return null;
+  }
+}
+
+/**
+ * An eslint rule ensuring that any require() of a local path (aka not a core
+ * module or a module dependency) includes a file extension (.js' or '.json').
+ * @type {RuleModule}
+ */
+const requireFileExtension = {
+  meta: {
+    docs: {
+      description: 'disallow require() without a file extension',
+      category: 'Best Practices',
+      recommended: false,
+    },
+    schema: [],
+    fixable: 'code',
+  },
+
+  create(context) {
+    return {
+      CallExpression(node) {
+        // Only look at instances of `require(moduleName: string)`.
+        if (node.type !== 'CallExpression') return;
+        if (node.callee.type !== 'Identifier' || node.callee.name !== 'require') return;
+        if (!node.arguments.length) return;
+        const arg0 = node.arguments[0];
+        if (arg0.type !== 'Literal' || typeof arg0.value !== 'string') return;
+
+        const requiredPath = arg0.value;
+
+        // If it's not a local file, we don't care.
+        if (!requiredPath.startsWith('.')) return;
+
+        // Check that `requiredPath` is resolvable from the source file.
+        const contextDirname = path.dirname(context.getFilename());
+        const resolvedRequiredPath = requireResolveOrNull(requiredPath, contextDirname);
+        if (!resolvedRequiredPath) {
+          return context.report({
+            node: node,
+            message: `Cannot resolve module '${requiredPath}'.`,
+          });
+        }
+
+        // If it has a file extension, it's good to go.
+        if (requiredPath.endsWith('.js')) return;
+        if (requiredPath.endsWith('.json')) return;
+
+        context.report({
+          node: node,
+          message: 'Local require path must have a file extension.',
+          fix(fixer) {
+            // Find the correct file extension/filename ending of the requiredPath.
+            let fixedPath = path.relative(contextDirname, resolvedRequiredPath);
+            if (!fixedPath.startsWith('.')) fixedPath = `./${fixedPath}`;
+
+            // Usually `fixedPath.startsWith(requiredPath)` and this will just add
+            // a suffix to the existing path, but sometimes humans write confusing
+            // paths, e.g. './lighthouse-core/lib/../lib/lh-error.js'. To cover both
+            // cases, double check that the paths resolve to the same file.
+            const resolvedFixedPath = requireResolveOrNull(fixedPath, contextDirname);
+
+            // If somehow they don't point to the same file, don't try to fix.
+            if (resolvedFixedPath !== resolvedRequiredPath) return null;
+
+            return fixer.replaceText(arg0, `'${fixedPath}'`);
+          },
+        });
+      },
+    };
+  },
+};
+
+module.exports = {
+  'require-file-extension': requireFileExtension,
+};

lighthouse-cli/commands/list-audits.js

@@ -5,7 +5,7 @@
  */
 'use strict';
 
-const lighthouse = require('../../lighthouse-core/');
+const lighthouse = require('../../lighthouse-core/index.js');
 
 function listAudits() {
   const audits = lighthouse.getAuditList().map((i) => i.replace(/\.js$/, ''));

lighthouse-cli/commands/list-trace-categories.js

@@ -5,7 +5,7 @@
  */
 'use strict';
 
-const lighthouse = require('../../lighthouse-core/');
+const lighthouse = require('../../lighthouse-core/index.js');
 
 function listTraceCategories() {
   const traceCategories = lighthouse.traceCategories;

lighthouse-cli/test/cli/cli-flags-test.js

@@ -7,7 +7,7 @@
 
 /* eslint-env jest */
 const assert = require('assert');
-const getFlags = require('../../cli-flags').getFlags;
+const getFlags = require('../../cli-flags.js').getFlags;
 
 describe('CLI bin', function() {
   it('all options should have descriptions', () => {

lighthouse-cli/test/cli/run-test.js

@@ -11,7 +11,7 @@ const path = require('path');
 const fs = require('fs');
 
 const run = require('../../run.js');
-const parseChromeFlags = require('../../run').parseChromeFlags;
+const parseChromeFlags = require('../../run.js').parseChromeFlags;
 const fastConfig = {
   'extends': 'lighthouse:default',
   'settings': {
@@ -21,10 +21,11 @@ const fastConfig = {
 
 // Map plugin name to fixture since not actually installed in node_modules/.
 jest.mock('lighthouse-plugin-simple', () => {
-  return require('../../../lighthouse-core/test/fixtures/config-plugins/lighthouse-plugin-simple/');
+  // eslint-disable-next-line max-len
+  return require('../../../lighthouse-core/test/fixtures/config-plugins/lighthouse-plugin-simple/plugin-simple.js');
 }, {virtual: true});
 
-const getFlags = require('../../cli-flags').getFlags;
+const getFlags = require('../../cli-flags.js').getFlags;
 
 describe('CLI run', function() {
   describe('LH round trip', () => {

lighthouse-cli/test/smokehouse/pwa2-expectations.js

@@ -5,7 +5,7 @@
  */
 'use strict';
 
-const pwaDetailsExpectations = require('./pwa-expectations').PWA_DETAILS_EXPECTATIONS;
+const pwaDetailsExpectations = require('./pwa-expectations.js').PWA_DETAILS_EXPECTATIONS;
 
 const jakeExpectations = {...pwaDetailsExpectations, hasShortName: false};
 

lighthouse-cli/test/smokehouse/pwa3-expectations.js

@@ -5,7 +5,7 @@
  */
 'use strict';
 
-const pwaDetailsExpectations = require('./pwa-expectations').PWA_DETAILS_EXPECTATIONS;
+const pwaDetailsExpectations = require('./pwa-expectations.js').PWA_DETAILS_EXPECTATIONS;
 
 const pwaRocksExpectations = {...pwaDetailsExpectations, hasIconsAtLeast512px: false};
 

lighthouse-cli/test/smokehouse/run-smoke.js

@@ -14,7 +14,7 @@ const log = require('lighthouse-logger');
 
 /** @param {string} str */
 const purpleify = str => `${log.purple}${str}${log.reset}`;
-const SMOKETESTS = require('./smoke-test-dfns').SMOKE_TEST_DFNS;
+const SMOKETESTS = require('./smoke-test-dfns.js').SMOKE_TEST_DFNS;
 
 /**
  * Display smokehouse output from child process

lighthouse-core/audits/byte-efficiency/byte-efficiency-audit.js

@@ -6,7 +6,7 @@
 'use strict';
 
 const Audit = require('../audit.js');
-const linearInterpolation = require('../../lib/statistics').linearInterpolation;
+const linearInterpolation = require('../../lib/statistics.js').linearInterpolation;
 const Interactive = require('../../computed/metrics/lantern-interactive.js');
 const i18n = require('../../lib/i18n/i18n.js');
 const NetworkRecords = require('../../computed/network-records.js');

lighthouse-core/audits/byte-efficiency/unminified-css.js

@@ -8,7 +8,7 @@
 const ByteEfficiencyAudit = require('./byte-efficiency-audit.js');
 const UnusedCSSRules = require('./unused-css-rules.js');
 const i18n = require('../../lib/i18n/i18n.js');
-const computeTokenLength = require('../../lib/minification-estimator').computeCSSTokenLength;
+const computeTokenLength = require('../../lib/minification-estimator.js').computeCSSTokenLength;
 
 const UIStrings = {
   /** Imperative title of a Lighthouse audit that tells the user to minify (remove whitespace) the page's CSS code. This is displayed in a list of audit titles that Lighthouse generates. */

lighthouse-core/audits/byte-efficiency/unminified-javascript.js

@@ -7,7 +7,7 @@
 
 const ByteEfficiencyAudit = require('./byte-efficiency-audit.js');
 const i18n = require('../../lib/i18n/i18n.js');
-const computeTokenLength = require('../../lib/minification-estimator').computeJSTokenLength;
+const computeTokenLength = require('../../lib/minification-estimator.js').computeJSTokenLength;
 
 const UIStrings = {
   /** Imperative title of a Lighthouse audit that tells the user to minify the page’s JS code to reduce file size. This is displayed in a list of audit titles that Lighthouse generates. */

lighthouse-core/audits/byte-efficiency/uses-long-cache-ttl.js

@@ -10,7 +10,7 @@ const parseCacheControl = require('parse-cache-control');
 const Audit = require('../audit.js');
 const NetworkRequest = require('../../lib/network-request.js');
 const URL = require('../../lib/url-shim.js');
-const linearInterpolation = require('../../lib/statistics').linearInterpolation;
+const linearInterpolation = require('../../lib/statistics.js').linearInterpolation;
 const i18n = require('../../lib/i18n/i18n.js');
 const NetworkRecords = require('../../computed/network-records.js');
 

lighthouse-core/audits/load-fast-enough-for-pwa.js

@@ -13,7 +13,7 @@
 
 const isDeepEqual = require('lodash.isequal');
 const Audit = require('./audit.js');
-const mobileThrottling = require('../config/constants').throttling.mobileSlow4G;
+const mobileThrottling = require('../config/constants.js').throttling.mobileSlow4G;
 const Interactive = require('../computed/metrics/interactive.js');
 const i18n = require('../lib/i18n/i18n.js');
 

lighthouse-core/index.js

@@ -70,7 +70,7 @@ function generateConfig(configJson, flags) {
 
 lighthouse.generateConfig = generateConfig;
 lighthouse.getAuditList = Runner.getAuditList;
-lighthouse.traceCategories = require('./gather/driver').traceCategories;
+lighthouse.traceCategories = require('./gather/driver.js').traceCategories;
 lighthouse.Audit = require('./audits/audit.js');
 lighthouse.Gatherer = require('./gather/gatherers/gatherer.js');
 lighthouse.NetworkRecords = require('./computed/network-records.js');

lighthouse-core/lib/dependency-graph/simulator/simulator.js

@@ -9,7 +9,7 @@ const BaseNode = require('../base-node.js');
 const TcpConnection = require('./tcp-connection.js');
 const ConnectionPool = require('./connection-pool.js');
 const DNSCache = require('./dns-cache.js');
-const mobileSlow4G = require('../../../config/constants').throttling.mobileSlow4G;
+const mobileSlow4G = require('../../../config/constants.js').throttling.mobileSlow4G;
 
 /** @typedef {BaseNode.Node} Node */
 /** @typedef {import('../network-node')} NetworkNode */

lighthouse-core/runner.js

@@ -18,7 +18,7 @@ const fs = require('fs');
 const path = require('path');
 const URL = require('./lib/url-shim.js');
 const Sentry = require('./lib/sentry.js');
-const generateReport = require('./report/report-generator').generateReport;
+const generateReport = require('./report/report-generator.js').generateReport;
 const LHError = require('./lib/lh-error.js');
 
 /** @typedef {import('./gather/connections/connection.js')} Connection */

lighthouse-core/scripts/benchmark.js

@@ -9,7 +9,7 @@
 
 /* eslint-disable no-console */
 
-const ultradumbBenchmark = require('../lib/page-functions').ultradumbBenchmark;
+const ultradumbBenchmark = require('../lib/page-functions.js').ultradumbBenchmark;
 
 console.log('Running ULTRADUMB™ benchmark 10 times...');
 

lighthouse-core/scripts/lantern/run-once.js

@@ -8,9 +8,9 @@
 
 const fs = require('fs');
 const path = require('path');
-const PredictivePerf = require('../../../lighthouse-core/audits/predictive-perf.js');
-const Simulator = require('../../../lighthouse-core/lib/dependency-graph/simulator/simulator.js');
-const traceSaver = require('../../../lighthouse-core/lib/lantern-trace-saver.js');
+const PredictivePerf = require('../../audits/predictive-perf.js');
+const Simulator = require('../../lib/dependency-graph/simulator/simulator.js');
+const traceSaver = require('../../lib/lantern-trace-saver.js');
 
 if (process.argv.length !== 4) throw new Error('Usage $0 <trace file> <devtools file>');
 

lighthouse-core/test/audits/byte-efficiency/render-blocking-resources-test.js

@@ -7,7 +7,7 @@
 
 const RenderBlockingResourcesAudit = require('../../../audits/byte-efficiency/render-blocking-resources.js'); // eslint-disable-line max-len
 
-const mobileSlow4G = require('../../../config/constants').throttling.mobileSlow4G;
+const mobileSlow4G = require('../../../config/constants.js').throttling.mobileSlow4G;
 const NetworkNode = require('../../../lib/dependency-graph/network-node.js');
 const CPUNode = require('../../../lib/dependency-graph/cpu-node.js');
 const Simulator = require('../../../lib/dependency-graph/simulator/simulator.js');

lighthouse-core/test/audits/load-fast-enough-for-pwa-test.js

@@ -6,7 +6,7 @@
 'use strict';
 
 const FastPWAAudit = require('../../audits/load-fast-enough-for-pwa.js');
-const mobileSlow4GThrottling = require('../../config/constants').throttling.mobileSlow4G;
+const mobileSlow4GThrottling = require('../../config/constants.js').throttling.mobileSlow4G;
 const assert = require('assert');
 const createTestTrace = require('../create-test-trace.js');
 const networkRecordsToDevtoolsLog = require('../network-records-to-devtools-log.js');

lighthouse-core/test/fixtures/invalid-audits/require-error.js

@@ -6,6 +6,7 @@
 'use strict';
 
 // NOTE: this require path does not resolve correctly.
+// eslint-disable-next-line local-rules/require-file-extension
 const LighthouseAudit = require('../terrible/path/come/on/audit.js');
 
 class RequireErrorAudit extends LighthouseAudit {

lighthouse-core/test/fixtures/invalid-gatherers/require-error.js

@@ -6,6 +6,7 @@
 'use strict';
 
 // NOTE: this require path does not resolve correctly.
+// eslint-disable-next-line local-rules/require-file-extension
 const LighthouseGatherer = require('../terrible/path/no/seriously/gatherer.js');
 
 class CustomGatherer extends LighthouseGatherer {}