120 lines
2.9 KiB
JavaScript
120 lines
2.9 KiB
JavaScript
function createListener(fn, that, type, once) {
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return {
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fn, that, type, once,
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bound: that ? fn.bind(that) : fn,
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}
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}
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export function EventEmitterMixin(Superclass) {
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return class EventEmitter extends Superclass {
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constructor(...args) {
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super(...args);
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this.$$events = Object.create(null);
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}
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addListener(typesOrType, fn, that) {
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return this.on(typesOrType, fn, that);
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}
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// Notify ALL the listeners!
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emit(type, ...args) {
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const typeListeners = this.$$events[type];
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if (typeListeners && typeListeners.length > 0) {
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this.emitToListeners(typeListeners, args);
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}
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}
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emitToListeners(listeners, args) {
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for (let i = 0; i < listeners.length; ++i) {
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const {once, type, fn, bound, that} = listeners[i];
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// Remove if only once.
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if (once) {
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this.offSingleEvent(type, fn);
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}
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// Fast path...
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if (0 === args.length) {
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bound()
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}
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else if (1 === args.length) {
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bound(args[0]);
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}
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else if (2 === args.length) {
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bound(args[0], args[1]);
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}
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else if (3 === args.length) {
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bound(args[0], args[1], args[2]);
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}
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else if (4 === args.length) {
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bound(args[0], args[1], args[2], args[3]);
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}
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else if (5 === args.length) {
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bound(args[0], args[1], args[2], args[3], args[4]);
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}
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// Slow path...
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else {
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fn.apply(that, args);
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}
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}
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}
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off(typesOrType, fn) {
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typesOrType = Array.isArray(typesOrType) ? typesOrType : [typesOrType];
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for (let i = 0; i < typesOrType.length; i++) {
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const type = typesOrType[i];
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this.offSingleEvent(type, fn);
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}
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return this;
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}
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offSingleEvent(type, fn) {
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if ('function' !== typeof fn) {
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// Only type.
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if (type in this.$$events) {
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this.$$events[type] = [];
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}
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return;
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}
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// Function.
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if (!(type in this.$$events)) {
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return;
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}
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this.$$events[type] = this.$$events[type].filter((listener) => {
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return listener.fn !== fn;
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});
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}
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on(typesOrType, fn, that = undefined) {
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this._on(typesOrType, fn, that, false);
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return this;
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}
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_on(typesOrType, fn, that, once) {
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typesOrType = Array.isArray(typesOrType) ? typesOrType : [typesOrType];
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for (let i = 0; i < typesOrType.length; i++) {
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const type = typesOrType[i];
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this.onSingleEvent(type, fn, that, once);
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}
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}
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once(types, fn, that = undefined) {
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this._on(types, fn, that, true);
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return this;
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}
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onSingleEvent(type, fn, that, once) {
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const listener = createListener(fn, that, type, once);
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if (!(type in this.$$events)) {
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this.$$events[type] = [];
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}
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this.$$events[type].push(listener);
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}
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removeListener(...args) {
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return this.off(...args);
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}
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}
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}
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