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/*
EventHandlerBase is the base class that implements the EventHandler interface methods for dispatching and receiving events.
*/
export default class EventHandlerBase {
constructor(){
this._listeners = new Map() // string type -> [listener, ...]
}
addEventListener(type, listener){
let listeners = this._listeners.get(type)
if(Array.isArray(listeners) === false){
listeners = []
this._listeners.set(type, listeners)
}
listeners.push(listener)
}
removeEventListener(type, listener){
let listeners = this._listeners.get(type)
if(Array.isArray(listeners) === false){
return
}
for(let i = 0; i < listeners.length; i++){
if(listeners[i] === listener){
listeners.splice(i, 1)
return
}
}
}
dispatchEvent(event){
let listeners = this._listeners.get(event.type)
if(Array.isArray(listeners) === false) return
for(let listener of listeners){
listener(event)
}
}
}