[doclint] lint events

This patch:
- adds event linting to the doclint
- improves `api.md` to add events and more information about
  classes reported by events.

References #14.

docs/api.md

@@ -13,6 +13,17 @@
   * [browser.stdout](#browserstdout)
   * [browser.version()](#browserversion)
 - [class: Page](#class-page)
+  * [event: 'consolemessage'](#event-consolemessage)
+  * [event: 'dialog'](#event-dialog)
+  * [event: 'frameattached'](#event-frameattached)
+  * [event: 'framedetached'](#event-framedetached)
+  * [event: 'framenavigated'](#event-framenavigated)
+  * [event: 'load'](#event-load)
+  * [event: 'pageerror'](#event-pageerror)
+  * [event: 'request'](#event-request)
+  * [event: 'requestfailed'](#event-requestfailed)
+  * [event: 'requestfinished'](#event-requestfinished)
+  * [event: 'response'](#event-response)
   * [page.addScriptTag(url)](#pageaddscripttagurl)
   * [page.click(selector)](#pageclickselector)
   * [page.close()](#pageclose)
@@ -179,6 +190,59 @@ browser.newPage().then(async page =>
 });
 ```
 
+#### event: 'consolemessage'
+- <[string]>
+
+Emitted when a page calls one of console API methods, e.g. `console.log`.
+
+#### event: 'dialog'
+- <[Dialog]>
+
+Emitted when a javascript dialog, such as `alert`, `prompt`, `confirm` or `beforeunload`, gets opened on the page. Puppeteer can take action to the dialog via dialog's [accept](#dialogacceptprompttext) or [dismiss](#dialogdismiss) methods.
+
+#### event: 'frameattached'
+- <[Frame]>
+
+Emitted when a frame gets attached.
+
+#### event: 'framedetached'
+- <[Frame]>
+
+Emitted when a frame gets detached.
+
+#### event: 'framenavigated'
+- <[Frame]>
+
+Emitted when a frame committed navigation.
+
+#### event: 'load'
+
+Emitted when a page's `load` event was dispatched.
+
+#### event: 'pageerror'
+- <[string]>
+
+Emitted when an unhandled exception happens on the page. The only argument of the event holds the exception message.
+
+#### event: 'request'
+- <[Request]>
+
+Emitted when a page issues a request. The [request] object is a read-only object. In order to intercept and mutate requests, see [page.setRequestInterceptor](#pagesetrequestinterceptorinterceptor)
+
+#### event: 'requestfailed'
+- <[Request]>
+
+Emitted when a request is failed.
+
+#### event: 'requestfinished'
+- <[Request]>
+
+Emitted when a request is successfully finished.
+
+#### event: 'response'
+- <[Response]>
+
+Emitted when a [response] is received.
 
 #### page.addScriptTag(url)
 - `url` <[string]> Url of a script to be added
@@ -373,6 +437,9 @@ This is a shortcut for [page.mainFrame().url()](#frameurl)
 Shortcut for [page.mainFrame().waitFor(selector)](#framewaitforselector).
 
 ### class: Dialog
+
+[Dialog] objects are dispatched by page via the ['dialog'](#event-dialog) event.
+
 #### dialog.accept([promptText])
 - `promptText` <[string]> A text to enter in prompt. Does not cause any effects if the dialog's `type` is not prompt.
 - returns: <[Promise]> Promise which resolves when the dialog has being accepted.
@@ -389,6 +456,14 @@ Shortcut for [page.mainFrame().waitFor(selector)](#framewaitforselector).
 Dialog's type, could be one of the `alert`, `beforeunload`, `confirm` and `prompt`.
 
 ### class: Frame
+
+At every point of time, page exposes its current frame tree via the [page.mainFrame()](#pagemainframe) and [frame.childFrames()](#framechildframes) methods.
+
+[Frame] object's lifecycle is controlled by three events, dispatched on the page object:
+- ['frameattached'](#event-frameattached) - fired when the frame gets attached to the page. Frame could be attached to the page only once.
+- ['framenavigated'](#event-framenavigated) - fired when the frame commits navigation to a different URL.
+- ['framedetached'](#event-framedetached) - fired when the frame gets detached from the page.  Frame could be detached from the page only once.
+
 #### frame.childFrames()
 - returns: <[Array]<[Frame]>>
 
@@ -446,6 +521,15 @@ immediately.
 
 ### class: Request
 
+Whenever the page sends a request, the following events are emitted by puppeteer's page:
+- ['request'](#event-request) emitted when the request is issued by the page.
+- ['response'](#event-response) emitted when/if the response is received for the request.
+- ['requestfinished'](#event-requestfinished) emitted when the response body is downloaded and the request is complete.
+
+If request fails at some point, then instead of 'requestfinished' event (and possibly instead of 'response' event), the  ['requestfailed'](#event-requestfailed) event is emitted.
+
+If request gets a 'redirect' response, the request is successfully finished with the 'requestfinished' event, and a new request is  issued to a redirected url.
+
 [Request] class represents requests which are sent by page. [Request] implements [Body] mixin, which in case of HTTP POST requests allows clients to call `request.json()` or `request.text()` to get different representations of request's body.
 
 #### request.headers
@@ -616,3 +700,4 @@ If there's already a header with name `name`, the header gets overwritten.
 [Request]: https://github.com/GoogleChrome/puppeteer/blob/master/docs/api.md#class-request  "Request"
 [Browser]: https://github.com/GoogleChrome/puppeteer/blob/master/docs/api.md#class-browser  "Browser"
 [Body]: https://github.com/GoogleChrome/puppeteer/blob/master/docs/api.md#class-body  "Body"
+[Dialog]: https://github.com/GoogleChrome/puppeteer/blob/master/docs/api.md#class-dialog  "Dialog"

utils/doclint/Documentation.js

@@ -66,6 +66,14 @@ class Documentation {
         errors.push(`Non-existing property found: ${className}.${propertyName}`);
       for (let propertyName of propertyDiff.missing)
         errors.push(`Property not found: ${className}.${propertyName}`);
+
+      const actualEvents = Array.from(actualClass.events.keys()).sort();
+      const expectedEvents = Array.from(expectedClass.events.keys()).sort();
+      const eventsDiff = diff(actualEvents, expectedEvents);
+      for (let eventName of eventsDiff.extra)
+        errors.push(`Non-existing event found in class ${className}: '${eventName}'`);
+      for (let eventName of eventsDiff.missing)
+        errors.push(`Event not found in class ${className}: '${eventName}'`);
     }
     return errors;
   }
@@ -110,12 +118,15 @@ Documentation.Class = class {
     this.members = new Map();
     this.properties = new Map();
     this.methods = new Map();
+    this.events = new Map();
     for (let member of membersArray) {
       this.members.set(member.name, member);
       if (member.type === 'method')
         this.methods.set(member.name, member);
       else if (member.type === 'property')
         this.properties.set(member.name, member);
+      else if (member.type === 'event')
+        this.events.set(member.name, member);
     }
   }
 };
@@ -156,6 +167,14 @@ Documentation.Member = class {
   static createProperty(name) {
     return new Documentation.Member('property', name, [], false, false);
   }
+
+  /**
+   * @param {string} name
+   * @return {!Documentation.Member}
+   */
+  static createEvent(name) {
+    return new Documentation.Member('event', name, [], false, false);
+  }
 };
 
 Documentation.Argument = class {

utils/doclint/JSBuilder.js

@@ -7,6 +7,8 @@ const Documentation = require('./Documentation');
 class JSOutline {
   constructor(text) {
     this.classes = [];
+    this.errors = [];
+    this._eventsByClassName = new Map();
     this._currentClassName = null;
     this._currentClassMembers = [];
 
@@ -17,9 +19,12 @@ class JSOutline {
         this._onClassDeclaration(node);
       else if (node.type === 'MethodDefinition')
         this._onMethodDefinition(node);
+      else if (node.type === 'AssignmentExpression')
+        this._onAssignmentExpression(node);
     });
     walker.walk(ast);
     this._flushClassIfNeeded();
+    this._recreateClassesWithEvents();
   }
 
   _onClassDeclaration(node) {
@@ -68,6 +73,24 @@ class JSOutline {
     return ESTreeWalker.SkipSubtree;
   }
 
+  _onAssignmentExpression(node) {
+    if (node.left.type !== 'MemberExpression' || node.right.type !== 'ObjectExpression')
+      return;
+    if (node.left.object.type !== 'Identifier' || node.left.property.type !== 'Identifier' || node.left.property.name !== 'Events')
+      return;
+    const className = node.left.object.name;
+    let events = this._eventsByClassName.get(className);
+    if (!events) {
+      events = [];
+      this._eventsByClassName.set(className, events);
+    }
+    for (let property of node.right.properties) {
+      if (property.type !== 'Property' || property.key.type !== 'Identifier' || property.value.type !== 'Literal')
+        continue;
+      events.push(Documentation.Member.createEvent(property.value.value));
+    }
+  }
+
   _flushClassIfNeeded() {
     if (this._currentClassName === null)
       return;
@@ -77,6 +100,14 @@ class JSOutline {
     this._currentClassMembers = [];
   }
 
+  _recreateClassesWithEvents() {
+    this.classes = this.classes.map(cls => {
+      let events = this._eventsByClassName.get(cls.name) || [];
+      let members = cls.membersArray.concat(events);
+      return new Documentation.Class(cls.name, members);
+    });
+  }
+
   _extractText(node) {
     if (!node)
       return null;

utils/doclint/MDBuilder.js

@@ -55,6 +55,7 @@ class MDOutline {
     const constructorRegex = /^new (\w+)\((.*)\)$/;
     const methodRegex = /^(\w+)\.(\w+)\((.*)\)$/;
     const propertyRegex = /^(\w+)\.(\w+)$/;
+    const eventRegex = /^event: '(\w+)'$/;
     let currentClassName = null;
     let currentClassMembers = [];
     for (const cls of classes) {
@@ -72,6 +73,9 @@ class MDOutline {
         } else if (propertyRegex.test(member.name)) {
           let match = member.name.match(propertyRegex);
           handleProperty.call(this, member, match[1], match[2]);
+        } else if (eventRegex.test(member.name)) {
+          let match = member.name.match(eventRegex);
+          handleEvent.call(this, member, match[1]);
         }
       }
       flushClassIfNeeded.call(this);
@@ -98,6 +102,14 @@ class MDOutline {
       currentClassMembers.push(Documentation.Member.createProperty(propertyName));
     }
 
+    function handleEvent(member, eventName) {
+      if (!currentClassName || !eventName) {
+        this.errors.push(`Failed to process header as event: ${member.name}`);
+        return;
+      }
+      currentClassMembers.push(Documentation.Member.createEvent(eventName));
+    }
+
     function flushClassIfNeeded() {
       if (currentClassName === null)
         return;

utils/doclint/lint.js

@@ -61,20 +61,44 @@ async function lint(page, docsFolderPath, jsFolderPath) {
  */
 function lintMarkdown(doc) {
   const errors = [];
-  // Methods should be sorted alphabetically.
   for (let cls of doc.classesArray) {
-    for (let i = 0; i < cls.membersArray.length - 1; ++i) {
-      // Constructor always goes first.
-      if (cls.membersArray[i].name === 'constructor') {
-        if (i > 0)
-          errors.push(`Constructor of ${cls.name} should go before other methods`);
-        continue;
-      }
+    let members = cls.membersArray;
+
+    // Events should go first.
+    let eventIndex = 0;
+    for (; eventIndex < members.length && members[eventIndex].type === 'event'; ++eventIndex);
+    for (; eventIndex < members.length && members[eventIndex].type !== 'event'; ++eventIndex);
+    if (eventIndex < members.length)
+      errors.push(`Events should go first. Event '${members[eventIndex].name}' in class ${cls.name} breaks order`);
+
+    // Constructor should be right after events and before all other members.
+    let constructorIndex = members.findIndex(member => member.type === 'method' && member.name === 'constructor');
+    if (constructorIndex > 0 && members[constructorIndex - 1].type !== 'event')
+      errors.push(`Constructor of ${cls.name} should go before other methods`);
+
+    // Events should be sorted alphabetically.
+    for (let i = 0; i < members.length - 1; ++i) {
       let member1 = cls.membersArray[i];
       let member2 = cls.membersArray[i + 1];
+      if (member1.type !== 'event' || member2.type !== 'event')
+        continue;
+      if (member1.name > member2.name)
+        errors.push(`Event '${member1.name}' in class ${cls.name} breaks alphabetic ordering of events`);
+    }
+
+    // All other members should be sorted alphabetically.
+    for (let i = 0; i < members.length - 1; ++i) {
+      let member1 = cls.membersArray[i];
+      let member2 = cls.membersArray[i + 1];
+      if (member1.type === 'event' || member2.type === 'event')
+        continue;
+      if (member1.type === 'method' && member1.name === 'constructor')
+        continue;
       if (member1.name > member2.name) {
-        let memberName = `${cls.name}.${member1.name}` + (member1.type === 'method' ? '()' : '');
-        errors.push(`${memberName} breaks alphabetic member sorting inside class ${cls.name}`);
+        let memberName = `${cls.name}.${member1.name}`;
+        if (member1.type === 'method')
+          memberName += '()';
+        errors.push(`${memberName} breaks alphabetic ordering of class members.`);
       }
     }
   }

utils/doclint/test/07-sorting/doc.md

@@ -1,11 +1,17 @@
 ### class: Foo
 
+#### event: 'c'
+
+#### event: 'a'
+
 #### foo.aaa()
 
-#### new Foo()
+#### event: 'b'
 
 #### foo.ddd
 
+#### new Foo()
+
 #### foo.ccc()
 
 #### foo.bbb()

utils/doclint/test/07-sorting/foo.js

@@ -9,3 +9,9 @@ class Foo {
 
   ccc() {}
 }
+
+Foo.Events = {
+  a: 'a',
+  b: 'b',
+  c: 'c'
+}

utils/doclint/test/09-event-errors/doc.md

@@ -0,0 +1,5 @@
+### class: Foo
+
+#### event: 'start'
+
+#### event: 'stop'

utils/doclint/test/09-event-errors/foo.js

@@ -0,0 +1,7 @@
+class Foo {
+}
+
+Foo.Events = {
+  Start: 'start',
+  Finish: 'finish',
+};

utils/doclint/test/golden/07-sorting.txt

@@ -1,3 +1,5 @@
+[MarkDown] Events should go first. Event 'b' in class Foo breaks order
 [MarkDown] Constructor of Foo should go before other methods
-[MarkDown] Foo.ddd breaks alphabetic member sorting inside class Foo
-[MarkDown] Foo.ccc() breaks alphabetic member sorting inside class Foo
+[MarkDown] Event 'c' in class Foo breaks alphabetic ordering of events
+[MarkDown] Foo.ddd breaks alphabetic ordering of class members.
+[MarkDown] Foo.ccc() breaks alphabetic ordering of class members.

utils/doclint/test/golden/09-event-errors.txt

@@ -0,0 +1,2 @@
+[MarkDown] Non-existing event found in class Foo: 'stop'
+[MarkDown] Event not found in class Foo: 'finish'

utils/doclint/test/test.js

@@ -39,6 +39,7 @@ describe('doclint', function() {
   it('06-duplicates', SX(test));
   it('07-sorting', SX(test));
   it('08-return', SX(test));
+  it('09-event-errors', SX(test));
 });
 
 async function test() {