/
evented.js
56 lines (45 loc) · 1.2 KB
/
evented.js
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import { isUndefined } from './utils/type-check';
export class Evented {
on(event, handler, ctx, once = false) {
if (isUndefined(this.bindings)) {
this.bindings = {};
}
if (isUndefined(this.bindings[event])) {
this.bindings[event] = [];
}
this.bindings[event].push({ handler, ctx, once });
return this;
}
once(event, handler, ctx) {
return this.on(event, handler, ctx, true);
}
off(event, handler) {
if (isUndefined(this.bindings) ||
isUndefined(this.bindings[event])) {
return this;
}
if (isUndefined(handler)) {
delete this.bindings[event];
} else {
this.bindings[event].forEach((binding, index) => {
if (binding.handler === handler) {
this.bindings[event].splice(index, 1);
}
});
}
return this;
}
trigger(event, ...args) {
if (!isUndefined(this.bindings) && this.bindings[event]) {
this.bindings[event].forEach((binding, index) => {
const { ctx, handler, once } = binding;
const context = ctx || this;
handler.apply(context, args);
if (once) {
this.bindings[event].splice(index, 1);
}
});
}
return this;
}
}