overleaf/services/web/frontend/js/utils/EventEmitter.js

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/* eslint-disable
camelcase,
max-len,
no-return-assign,
no-unused-vars,
*/
// TODO: This file was created by bulk-decaffeinate.
// Fix any style issues and re-enable lint.
/*
* decaffeinate suggestions:
* DS101: Remove unnecessary use of Array.from
* DS102: Remove unnecessary code created because of implicit returns
* DS207: Consider shorter variations of null checks
* Full docs: https://github.com/decaffeinate/decaffeinate/blob/master/docs/suggestions.md
*/
// Simple event emitter implementation, but has a slightly unusual API for
// removing specific listeners. If a specific listener needs to be removed
// (instead of all listeners), then it needs to use a "namespace":
// Create a listener on the foo event with bar namespace: .on 'foo.bar'
// Trigger all events for the foo event (including namespaces): .trigger 'foo'
// Remove all listeners for the foo event (including namespaces): .off 'foo'
// Remove a listener for the foo event with the bar namespace: .off 'foo.bar'
let EventEmitter
export default EventEmitter = class EventEmitter {
on(event, callback) {
let namespace
if (!this.events) {
this.events = {}
}
;[event, namespace] = Array.from(event.split('.'))
if (!this.events[event]) {
this.events[event] = []
}
return this.events[event].push({
callback,
namespace,
})
}
off(event) {
if (!this.events) {
this.events = {}
}
if (event != null) {
let namespace
;[event, namespace] = Array.from(event.split('.'))
if (namespace == null) {
// Clear all listeners for event
return delete this.events[event]
} else {
// Clear only namespaced listeners
const remaining_events = []
for (const callback of Array.from(this.events[event] || [])) {
if (callback.namespace !== namespace) {
remaining_events.push(callback)
}
}
return (this.events[event] = remaining_events)
}
} else {
// Remove all listeners
return (this.events = {})
}
}
trigger(event, ...args) {
if (!this.events) {
this.events = {}
}
return Array.from(this.events[event] || []).map(callback =>
callback.callback(...Array.from(args || []))
)
}
emit(...args) {
return this.trigger(...Array.from(args || []))
}
}