Page MenuHomec4science
Files F101446157

event-target.js
No OneTemporary
Actions

File Metadata

Created
Mon, Feb 10, 13:39

event-target.js
View Options

'use strict';
const { kForOnEventAttribute, kListener } = require('./constants');
const kCode = Symbol('kCode');
const kData = Symbol('kData');
const kError = Symbol('kError');
const kMessage = Symbol('kMessage');
const kReason = Symbol('kReason');
const kTarget = Symbol('kTarget');
const kType = Symbol('kType');
const kWasClean = Symbol('kWasClean');
/**
* Class representing an event.
*/
class Event {
/**
* Create a new `Event`.
*
* @param {String} type The name of the event
* @throws {TypeError} If the `type` argument is not specified
*/
constructor(type) {
this[kTarget] = null;
this[kType] = type;
}
/**
* @type {*}
*/
get target() {
return this[kTarget];
}
/**
* @type {String}
*/
get type() {
return this[kType];
}
}
Object.defineProperty(Event.prototype, 'target', { enumerable: true });
Object.defineProperty(Event.prototype, 'type', { enumerable: true });
/**
* Class representing a close event.
*
* @extends Event
*/
class CloseEvent extends Event {
/**
* Create a new `CloseEvent`.
*
* @param {String} type The name of the event
* @param {Object} [options] A dictionary object that allows for setting
* attributes via object members of the same name
* @param {Number} [options.code=0] The status code explaining why the
* connection was closed
* @param {String} [options.reason=''] A human-readable string explaining why
* the connection was closed
* @param {Boolean} [options.wasClean=false] Indicates whether or not the
* connection was cleanly closed
*/
constructor(type, options = {}) {
super(type);
this[kCode] = options.code === undefined ? 0 : options.code;
this[kReason] = options.reason === undefined ? '' : options.reason;
this[kWasClean] = options.wasClean === undefined ? false : options.wasClean;
}
/**
* @type {Number}
*/
get code() {
return this[kCode];
}
/**
* @type {String}
*/
get reason() {
return this[kReason];
}
/**
* @type {Boolean}
*/
get wasClean() {
return this[kWasClean];
}
}
Object.defineProperty(CloseEvent.prototype, 'code', { enumerable: true });
Object.defineProperty(CloseEvent.prototype, 'reason', { enumerable: true });
Object.defineProperty(CloseEvent.prototype, 'wasClean', { enumerable: true });
/**
* Class representing an error event.
*
* @extends Event
*/
class ErrorEvent extends Event {
/**
* Create a new `ErrorEvent`.
*
* @param {String} type The name of the event
* @param {Object} [options] A dictionary object that allows for setting
* attributes via object members of the same name
* @param {*} [options.error=null] The error that generated this event
* @param {String} [options.message=''] The error message
*/
constructor(type, options = {}) {
super(type);
this[kError] = options.error === undefined ? null : options.error;
this[kMessage] = options.message === undefined ? '' : options.message;
}
/**
* @type {*}
*/
get error() {
return this[kError];
}
/**
* @type {String}
*/
get message() {
return this[kMessage];
}
}
Object.defineProperty(ErrorEvent.prototype, 'error', { enumerable: true });
Object.defineProperty(ErrorEvent.prototype, 'message', { enumerable: true });
/**
* Class representing a message event.
*
* @extends Event
*/
class MessageEvent extends Event {
/**
* Create a new `MessageEvent`.
*
* @param {String} type The name of the event
* @param {Object} [options] A dictionary object that allows for setting
* attributes via object members of the same name
* @param {*} [options.data=null] The message content
*/
constructor(type, options = {}) {
super(type);
this[kData] = options.data === undefined ? null : options.data;
}
/**
* @type {*}
*/
get data() {
return this[kData];
}
}
Object.defineProperty(MessageEvent.prototype, 'data', { enumerable: true });
/**
* This provides methods for emulating the `EventTarget` interface. It's not
* meant to be used directly.
*
* @mixin
*/
const EventTarget = {
/**
* Register an event listener.
*
* @param {String} type A string representing the event type to listen for
* @param {(Function|Object)} handler The listener to add
* @param {Object} [options] An options object specifies characteristics about
* the event listener
* @param {Boolean} [options.once=false] A `Boolean` indicating that the
* listener should be invoked at most once after being added. If `true`,
* the listener would be automatically removed when invoked.
* @public
*/
addEventListener(type, handler, options = {}) {
for (const listener of this.listeners(type)) {
if (
!options[kForOnEventAttribute] &&
listener[kListener] === handler &&
!listener[kForOnEventAttribute]
) {
return;
}
}
let wrapper;
if (type === 'message') {
wrapper = function onMessage(data, isBinary) {
const event = new MessageEvent('message', {
data: isBinary ? data : data.toString()
});
event[kTarget] = this;
callListener(handler, this, event);
};
} else if (type === 'close') {
wrapper = function onClose(code, message) {
const event = new CloseEvent('close', {
code,
reason: message.toString(),
wasClean: this._closeFrameReceived && this._closeFrameSent
});
event[kTarget] = this;
callListener(handler, this, event);
};
} else if (type === 'error') {
wrapper = function onError(error) {
const event = new ErrorEvent('error', {
error,
message: error.message
});
event[kTarget] = this;
callListener(handler, this, event);
};
} else if (type === 'open') {
wrapper = function onOpen() {
const event = new Event('open');
event[kTarget] = this;
callListener(handler, this, event);
};
} else {
return;
}
wrapper[kForOnEventAttribute] = !!options[kForOnEventAttribute];
wrapper[kListener] = handler;
if (options.once) {
this.once(type, wrapper);
} else {
this.on(type, wrapper);
}
},
/**
* Remove an event listener.
*
* @param {String} type A string representing the event type to remove
* @param {(Function|Object)} handler The listener to remove
* @public
*/
removeEventListener(type, handler) {
for (const listener of this.listeners(type)) {
if (listener[kListener] === handler && !listener[kForOnEventAttribute]) {
this.removeListener(type, listener);
break;
}
}
}
};
module.exports = {
CloseEvent,
ErrorEvent,
Event,
EventTarget,
MessageEvent
};
/**
* Call an event listener
*
* @param {(Function|Object)} listener The listener to call
* @param {*} thisArg The value to use as `this`` when calling the listener
* @param {Event} event The event to pass to the listener
* @private
*/
function callListener(listener, thisArg, event) {
if (typeof listener === 'object' && listener.handleEvent) {
listener.handleEvent.call(listener, event);
} else {
listener.call(thisArg, event);
}
}

Event Timeline

c4science · Help