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observable.ts
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179 lines (148 loc) · 5.1 KB
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import types = require("utils/types");
import definition = require("data/observable");
interface ListenerEntry {
callback: (data: definition.EventData) => void;
thisArg: any;
}
export module knownEvents {
export var propertyChange = "propertyChange";
}
export class Observable implements definition.Observable {
private _observers = {};
constructor(json?: any) {
if (json) {
for (var prop in json) {
if (json.hasOwnProperty(prop)) {
this.set(prop, json[prop]);
}
}
}
}
get typeName(): string {
return types.getClass(this);
}
public on(eventNames: string, callback: (data: definition.EventData) => void, thisArg?: any) {
this.addEventListener(eventNames, callback, thisArg);
}
public off(eventNames: string, callback?: any) {
this.removeEventListener(eventNames, callback);
}
public addEventListener(eventNames: string, callback: (data: definition.EventData) => void, thisArg?: any) {
types.verifyCallback(callback);
var events: Array<string> = eventNames.split(",");
for (var i = 0, l = events.length; i < l; i++) {
var event = events[i].trim();
var list = this._getEventList(event, true);
// TODO: Performance optimization - if we do not have the thisArg specified, do not wrap the callback in additional object (ObserveEntry)
list.push({
callback: callback,
thisArg: thisArg
});
}
}
public removeEventListener(eventNames: string, callback?: any, thisArg?: any) {
var events: Array<string> = eventNames.split(",");
for (var i = 0, l = events.length; i < l; i++) {
var event = events[i].trim();
if (callback) {
var list = this._getEventList(event, false);
if (list) {
var index = this._indexOfListener(list, callback, thisArg);
if (index >= 0) {
list.splice(index, 1);
}
if (list.length === 0) {
delete this._observers[event];
}
}
}
else {
this._observers[event] = undefined;
delete this._observers[event];
}
}
}
public set(name: string, value: any) {
// TODO: Parameter validation
if (this[name] === value) {
return;
}
// create data for the change
var data = this._createPropertyChangeData(name, value);
this._setCore(data);
this.notify(data);
// TODO: Maybe we need to update source object used in the constructor as well?
}
public get(name: string): any {
return this[name];
}
public _setCore(data: definition.PropertyChangeData) {
this[data.propertyName] = data.value;
}
public notify(data: definition.EventData) {
var observers = this._getEventList(data.eventName);
if (!observers) {
return;
}
var i;
var entry: ListenerEntry;
for (i = 0; i < observers.length; i++) {
entry = observers[i];
if (entry.thisArg) {
entry.callback.apply(entry.thisArg, [data]);
} else {
entry.callback(data);
}
}
}
public hasListeners(eventName: string) {
return eventName in this._observers;
}
public _createPropertyChangeData(name: string, value: any): definition.PropertyChangeData {
return {
eventName: knownEvents.propertyChange,
propertyName: name,
object: this,
value: value
};
}
public _emit(eventNames: string) {
var events: Array<string> = eventNames.split(",");
for (var i = 0, l = events.length; i < l; i++) {
var event = events[i].trim();
this.notify({ eventName: event, object: this });
}
}
private _getEventList(eventName: string, createIfNeeded?: boolean): Array<ListenerEntry> {
if (!eventName) {
throw new TypeError("EventName must be valid string.");
}
var list = <Array<ListenerEntry>>this._observers[eventName];
if (!list && createIfNeeded) {
list = [];
this._observers[eventName] = list;
}
return list;
}
private _indexOfListener(list: Array<ListenerEntry>, callback: (data: definition.EventData) => void, thisArg?: any): number {
var i;
var entry: ListenerEntry;
for (i = 0; i < list.length; i++) {
entry = list[i];
if (thisArg) {
if (entry.callback === callback && entry.thisArg === thisArg) {
return i;
}
}
else {
if (entry.callback === callback) {
return i;
}
}
}
return -1;
}
public toString(): string {
return this.typeName;
}
}