move out of WIP

Author: patrickhulce

lighthouse-cli/test/smokehouse/byte-config.js

@@ -16,6 +16,7 @@ module.exports = {
       'uses-webp-images',
       'uses-optimized-images',
       'uses-responsive-images',
+      'unminified-javascript',
       'unused-css-rules',
       'unused-javascript',
     ],

lighthouse-cli/test/smokehouse/byte-efficiency/expectations.js

@@ -13,6 +13,17 @@ module.exports = [
     initialUrl: 'http://localhost:10200/byte-efficiency/tester.html',
     url: 'http://localhost:10200/byte-efficiency/tester.html',
     audits: {
+      'unminified-javascript': {
+        score: '<100',
+        extendedInfo: {
+          value: {
+            wastedKb: 14,
+            results: {
+              length: 1,
+            },
+          },
+        },
+      },
       'unused-css-rules': {
         score: '<100',
         extendedInfo: {

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

@@ -18,9 +18,10 @@ class UnminifiedJavaScript extends ByteEfficiencyAudit {
   static get meta() {
     return {
       name: 'unminified-javascript',
-      description: 'Unminified JavaScript',
+      description: 'Minify JavaScript',
       informative: true,
-      helpText: 'Minify JavaScript to save network bytes.',
+      helpText: 'Minifying JavaScript files can reduce payload sizes and script parse time.' +
+        '[Learn more](https://developers.google.com/speed/docs/insights/MinifyResources).',
       requiredArtifacts: ['Scripts', 'devtoolsLogs'],
     };
   }
@@ -31,21 +32,16 @@ class UnminifiedJavaScript extends ByteEfficiencyAudit {
    */
   static computeWaste(scriptContent, networkRecord) {
     const contentLength = scriptContent.length;
-    let tokenLength = 0;
-    let tokenLengthWithMangling = 0;
+    let totalTokenLength = 0;
 
     const tokens = esprima.tokenize(scriptContent);
     for (const token of tokens) {
-      tokenLength += token.value.length;
-      // assume all identifiers could be reduced to a single character
-      tokenLengthWithMangling += token.type === 'Identifier' ? 1 : token.value.length;
+      totalTokenLength += token.value.length;
     }
 
-    if (1 - tokenLength / contentLength < IGNORE_THRESHOLD_IN_PERCENT) return null;
-
     const totalBytes = ByteEfficiencyAudit.estimateTransferSize(networkRecord, contentLength,
       'script');
-    const wastedRatio = 1 - (tokenLength + tokenLengthWithMangling) / (2 * contentLength);
+    const wastedRatio = 1 - totalTokenLength / contentLength;
     const wastedBytes = Math.round(totalBytes * wastedRatio);
 
     return {
@@ -61,15 +57,17 @@ class UnminifiedJavaScript extends ByteEfficiencyAudit {
    * @return {!Audit.HeadingsResult}
    */
   static audit_(artifacts, networkRecords) {
-    const scriptsByUrl = artifacts.Scripts;
-
     const results = [];
-    for (const [url, scriptContent] of scriptsByUrl.entries()) {
+    for (const [url, scriptContent] of artifacts.Scripts.entries()) {
       const networkRecord = networkRecords.find(record => record.url === url);
       if (!networkRecord || !scriptContent) continue;
 
       const result = UnminifiedJavaScript.computeWaste(scriptContent, networkRecord);
-      if (!result || result.wastedBytes < IGNORE_THRESHOLD_IN_BYTES) continue;
+
+      // If the ratio is minimal, the file is likely already minified, so ignore it.
+      // If the total number of bytes to be saved is quite small, it's also safe to ignore.
+      if (result.wastedRatio < IGNORE_THRESHOLD_IN_PERCENT ||
+          result.wastedBytes < IGNORE_THRESHOLD_IN_BYTES) continue;
       results.push(result);
     }
 

lighthouse-core/gather/gatherers/scripts.js

@@ -9,7 +9,7 @@ const Gatherer = require('./gatherer');
 const WebInspector = require('../../lib/web-inspector');
 
 /**
- * @fileoverview Gets JavaScript content
+ * @fileoverview Gets JavaScript file content
  */
 class Scripts extends Gatherer {
   /**
@@ -22,13 +22,13 @@ class Scripts extends Gatherer {
 
     const scriptContentMap = new Map();
     const scriptRecords = traceData.networkRecords
-      .filter(record => record.resourceType() === WebInspector.resourceTypes.Script)
+      .filter(record => record.resourceType() === WebInspector.resourceTypes.Script);
 
     return scriptRecords.reduce((promise, record) => {
       return promise
         .then(() => {
           return driver.getRequestContent(record.requestId)
-            .catch(err => null)
+            .catch(_ => null)
             .then(content => {
               if (!content) return;
               scriptContentMap.set(record.url, content);

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

@@ -0,0 +1,90 @@
+/**
+ * @license Copyright 2017 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';
+
+const KB = 1024;
+const UnminifiedJavascriptAudit =
+  require('../../../audits/byte-efficiency/unminified-javascript.js');
+const assert = require('assert');
+
+/* eslint-env mocha */
+
+describe('Page uses optimized responses', () => {
+  it('fails when given unminified scripts', () => {
+    const auditResult = UnminifiedJavascriptAudit.audit_({
+      Scripts: new Map([
+        [
+          'foo.js',
+          `
+            var foo = new Set();
+            foo.add(1);
+            foo.add(2);
+
+            if (foo.has(2)) {
+              console.log('hello!')
+            }
+          `,
+        ],
+        [
+          'other.js',
+          `
+            const foo = new Set();
+            foo.add(1);
+
+            async function go() {
+              await foo.has(1)
+              console.log('yay esnext!')
+            }
+          `,
+        ],
+      ]),
+    }, [
+      {url: 'foo.js', _transferSize: 20 * KB, _resourceType: {_name: 'script'}},
+      {url: 'other.js', _transferSize: 50 * KB, _resourceType: {_name: 'script'}},
+    ]);
+
+    assert.equal(auditResult.results.length, 2);
+    assert.equal(auditResult.results[0].url, 'foo.js');
+    assert.equal(Math.round(auditResult.results[0].wastedPercent), 57);
+    assert.equal(Math.round(auditResult.results[0].wastedBytes / 1024), 11);
+    assert.equal(auditResult.results[1].url, 'other.js');
+    assert.equal(Math.round(auditResult.results[1].wastedPercent), 53);
+    assert.equal(Math.round(auditResult.results[1].wastedBytes / 1024), 27);
+  });
+
+  it('passes when scripts are already minified', () => {
+    const auditResult = UnminifiedJavascriptAudit.audit_({
+      Scripts: new Map([
+        [
+          'foo.js',
+          'var f=new Set();f.add(1);f.add(2);if(f.has(2))console.log(1234)',
+        ],
+        [
+          'other.js',
+          `
+            const foo = new Set();
+            foo.add(1);
+
+            async function go() {
+              await foo.has(1)
+              console.log('yay esnext!')
+            }
+          `,
+        ],
+        [
+          'invalid.js',
+          'for{(wtf',
+        ],
+      ]),
+    }, [
+      {url: 'foo.js', _transferSize: 20 * KB, _resourceType: {_name: 'script'}},
+      {url: 'other.js', _transferSize: 3 * KB, _resourceType: {_name: 'script'}},
+      {url: 'invalid.js', _transferSize: 20 * KB, _resourceType: {_name: 'script'}},
+    ]);
+
+    assert.equal(auditResult.results.length, 0);
+  });
+});