new_audit(dobetterweb): add new audit for doctype

lighthouse-core/audits/dobetterweb/doctype.js

@@ -0,0 +1,73 @@
+/**
+ * @license Copyright 2018 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 Audit = require('../audit');
+
+class Doctype extends Audit {
+  /**
+   * @return {LH.Audit.Meta}
+   */
+  static get meta() {
+    return {
+      id: 'doctype',
+      title: 'Page has the HTML doctype',
+      failureTitle: 'Page is missing the HTML doctype',
+      description: 'Specifying a doctype prevents the browser from switching to quirks-mode.' +
+                'Read more on the ' +
+                '[MDN Web Docs page](https://developer.mozilla.org/en-US/docs/Glossary/Doctype)',
+      requiredArtifacts: ['Doctype'],
+    };
+  }
+
+  /**
+   * @param {LH.Artifacts} artifacts
+   * @return {LH.Audit.Product}
+   */
+  static audit(artifacts) {
+    if (!artifacts.Doctype) {
+      return {
+        rawValue: false,
+        explanation: 'Document must contain a doctype',
+      };
+    }
+
+    // only set constants once we know there is a doctype
+    const doctypeName = artifacts.Doctype.name.trim();
+    const doctypePublicId = artifacts.Doctype.publicId;
+    const doctypeSystemId = artifacts.Doctype.systemId;
+
+    if (doctypePublicId !== '') {
+      return {
+        rawValue: false,
+        explanation: 'Expected publicId to be an empty string',
+      };
+    }
+
+    if (doctypeSystemId !== '') {
+      return {
+        rawValue: false,
+        explanation: 'Expected systemId to be an empty string',
+      };
+    }
+
+    /* Note that the value for name is case sensitive,
+       and must be the string `html`. For details see:
+       https://html.spec.whatwg.org/multipage/parsing.html#the-initial-insertion-mode */
+    if (doctypeName === 'html') {
+      return {
+        rawValue: true,
+      };
+    } else {
+      return {
+        rawValue: false,
+        explanation: 'Doctype name must be the lowercase string `html`',
+      };
+    }
+  }
+}
+
+module.exports = Doctype;

lighthouse-core/config/default-config.js

@@ -1,5 +1,5 @@
 /**
- * @license Copyright 2017 Google Inc. All Rights Reserved.
+ * @license Copyright 2018 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.
  */
@@ -31,6 +31,7 @@ module.exports = {
       'accessibility',
       'dobetterweb/anchors-with-no-rel-noopener',
       'dobetterweb/appcache',
+      'dobetterweb/doctype',
       'dobetterweb/domstats',
       'dobetterweb/js-libraries',
       'dobetterweb/optimized-images',
@@ -161,6 +162,7 @@ module.exports = {
     'byte-efficiency/uses-responsive-images',
     'byte-efficiency/efficient-animated-content',
     'dobetterweb/appcache-manifest',
+    'dobetterweb/doctype',
     'dobetterweb/dom-size',
     'dobetterweb/external-anchors-use-rel-noopener',
     'dobetterweb/geolocation-on-start',
@@ -373,6 +375,7 @@ module.exports = {
         {id: 'no-document-write', weight: 1},
         {id: 'external-anchors-use-rel-noopener', weight: 1},
         {id: 'geolocation-on-start', weight: 1},
+        {id: 'doctype', weight: 1},
         {id: 'no-vulnerable-libraries', weight: 1},
         {id: 'notification-on-start', weight: 1},
         {id: 'deprecations', weight: 1},

lighthouse-core/gather/gatherers/dobetterweb/doctype.js

@@ -0,0 +1,36 @@
+/**
+ * @license Copyright 2018 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 Gatherer = require('../gatherer');
+
+/**
+ * Get and return `name`, `publicId`, `systemId` from
+ * `document.doctype`
+ * @return {{name: string, publicId: string, systemId: string} | null}
+ */
+function getDoctype() {
+  // An example of this is warnerbros.com/archive/spacejam/movie/jam.htm
+  if (!document.doctype) { // eslint-disable-line no-undef
+    return null;
+  }
+
+  const {name, publicId, systemId} = document.doctype; // eslint-disable-line no-undef
+  return {name, publicId, systemId};
+}
+
+class Doctype extends Gatherer {
+  /**
+   * @param {LH.Gatherer.PassContext} passContext
+   * @return {Promise<LH.Artifacts['Doctype']>}
+   */
+  afterPass(passContext) {
+    const driver = passContext.driver;
+    return driver.evaluateAsync(`(${getDoctype.toString()}())`);
+  }
+}
+
+module.exports = Doctype;

lighthouse-core/test/audits/dobetterweb/doctype-test.js

@@ -0,0 +1,80 @@
+/**
+ * @license Copyright 2018 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 Audit = require('../../../audits/dobetterweb/doctype.js');
+const assert = require('assert');
+
+/* eslint-env mocha */
+
+describe('DOBETTERWEB: doctype audit', () => {
+  it('fails when document does not contain a doctype', () => {
+    const auditResult = Audit.audit({
+      Doctype: null,
+    });
+    assert.equal(auditResult.rawValue, false);
+    assert.equal(auditResult.explanation, 'Document must contain a doctype');
+  });
+
+  it('fails when the value of the name attribute is a value other then lowercase "html"', () => {
+    const auditResult = Audit.audit({
+      Doctype: {
+        name: 'xml',
+        publicId: '',
+        systemId: '',
+      },
+    });
+    assert.equal(auditResult.rawValue, false);
+    assert.equal(auditResult.explanation, 'Doctype name must be the lowercase string `html`');
+  });
+
+  it('fails when the value of the name attribute is not the lowercase string "html"', () => {
+    const auditResult = Audit.audit({
+      Doctype: {
+        name: 'HTML',
+        publicId: '',
+        systemId: '',
+      },
+    });
+    assert.equal(auditResult.rawValue, false);
+    assert.equal(auditResult.explanation, 'Doctype name must be the lowercase string `html`');
+  });
+
+  it('fails when the publicId attribute is not an empty string', () => {
+    const auditResult = Audit.audit({
+      Doctype: {
+        name: 'html',
+        publicId: '189655',
+        systemId: '',
+      },
+    });
+    assert.equal(auditResult.rawValue, false);
+    assert.equal(auditResult.explanation, 'Expected publicId to be an empty string');
+  });
+
+  it('fails when the systemId attribute is not an empty string', () => {
+    const auditResult = Audit.audit({
+      Doctype: {
+        name: 'html',
+        publicId: '',
+        systemId: '189655',
+      },
+    });
+    assert.equal(auditResult.rawValue, false);
+    assert.equal(auditResult.explanation, 'Expected systemId to be an empty string');
+  });
+
+  it('succeeds when document contains a doctype, and the name value is "html"', () => {
+    const auditResult = Audit.audit({
+      Doctype: {
+        name: 'html',
+        publicId: '',
+        systemId: '',
+      },
+    });
+    assert.equal(auditResult.rawValue, true);
+  });
+});

lighthouse-core/test/results/artifacts/artifacts.json

@@ -2521,5 +2521,10 @@
   },
   "HTMLWithoutJavaScript": {
     "bodyText": "Do better web tester page\nHi there!\ntouchmove section\n "
+  },
+  "Doctype": {
+    "name": "html",
+    "systemId": "",
+    "publicId": ""
   }
 }

lighthouse-core/test/results/sample_v2.json

@@ -2202,6 +2202,14 @@
       "rawValue": false,
       "displayValue": "Found \"clock.appcache\""
     },
+    "doctype": {
+      "id": "doctype",
+      "title": "Page has the HTML doctype",
+      "description": "Specifying a doctype prevents the browser from switching to quirks-mode.Read more on the [MDN Web Docs page](https://developer.mozilla.org/en-US/docs/Glossary/Doctype)",
+      "score": 1,
+      "scoreDisplayMode": "binary",
+      "rawValue": true
+    },
     "dom-size": {
       "id": "dom-size",
       "title": "Avoids an excessive DOM size",
@@ -3261,6 +3269,10 @@
           "id": "geolocation-on-start",
           "weight": 1
         },
+        {
+          "id": "doctype",
+          "weight": 1
+        },
         {
           "id": "no-vulnerable-libraries",
           "weight": 1
@@ -3287,7 +3299,7 @@
         }
       ],
       "id": "best-practices",
-      "score": 0
+      "score": 0.07
     },
     "seo": {
       "title": "SEO",

typings/artifacts.d.ts

@@ -56,6 +56,9 @@ declare global {
       CrawlableLinks: {href: string, text: string}[];
       /** CSS coverage information for styles used by page's final state. */
       CSSUsage: {rules: Crdp.CSS.RuleUsage[], stylesheets: Artifacts.CSSStyleSheetInfo[]};
+      /** Information on the document's doctype(or null if not present), specifically the name, publicId, and systemId.
+          All properties default to an empty string if not present */
+      Doctype: Artifacts.Doctype | null;
       /** Information on the size of all DOM nodes in the page and the most extreme members. */
       DOMStats: Artifacts.DOMStats;
       /** Relevant attributes and child properties of all <object>s, <embed>s and <applet>s in the page. */
@@ -173,6 +176,12 @@ declare global {
         content: string;
       }
 
+      export interface Doctype {
+        name: string;
+        publicId: string;
+        systemId: string;
+      }
+
       export interface DOMStats {
         totalDOMNodes: number;
         width: {max: number, pathToElement: Array<string>, snippet: string};