56 lines
1.4 KiB
JavaScript
56 lines
1.4 KiB
JavaScript
|
import Operator from "../Operator.js";
|
||
|
|
||
|
export default class MapOperator extends Operator {
|
||
|
constructor(source, mapper, updater) {
|
||
|
super(source);
|
||
|
this._mapper = mapper;
|
||
|
this._updater = updater;
|
||
|
this._mappedValues = new Map();
|
||
|
}
|
||
|
|
||
|
onAdd(key, value) {
|
||
|
const mappedValue = this._mapper(value);
|
||
|
this._mappedValues.set(key, mappedValue);
|
||
|
this.emitAdd(key, mappedValue);
|
||
|
}
|
||
|
|
||
|
onRemove(key, _value) {
|
||
|
const mappedValue = this._mappedValues.get(key);
|
||
|
if (this._mappedValues.delete(key)) {
|
||
|
this.emitRemove(key, mappedValue);
|
||
|
}
|
||
|
}
|
||
|
|
||
|
onChange(key, value, params) {
|
||
|
const mappedValue = this._mappedValues.get(key);
|
||
|
if (mappedValue !== undefined) {
|
||
|
const newParams = this._updater(value, params);
|
||
|
if (newParams !== undefined) {
|
||
|
this.emitChange(key, mappedValue, newParams);
|
||
|
}
|
||
|
}
|
||
|
}
|
||
|
|
||
|
onSubscribeFirst() {
|
||
|
for (let [key, value] of this._source) {
|
||
|
const mappedValue = this._mapper(value);
|
||
|
this._mappedValues.set(key, mappedValue);
|
||
|
}
|
||
|
super.onSubscribeFirst();
|
||
|
}
|
||
|
|
||
|
onUnsubscribeLast() {
|
||
|
super.onUnsubscribeLast();
|
||
|
this._mappedValues.clear();
|
||
|
}
|
||
|
|
||
|
onReset() {
|
||
|
this._mappedValues.clear();
|
||
|
this.emitReset();
|
||
|
}
|
||
|
|
||
|
[Symbol.iterator]() {
|
||
|
return this._mappedValues.entries()[Symbol.iterator];
|
||
|
}
|
||
|
}
|