92 lines
2.1 KiB
TypeScript
92 lines
2.1 KiB
TypeScript
|
type Untap = () => void
|
||
|
|
type UntapFromSource = () => void
|
||
|
|
|
||
|
|
interface IProps<V> {
|
||
|
|
tapToSource: (cb: (payload: V) => void) => UntapFromSource
|
||
|
|
}
|
||
|
|
|
||
|
|
type Listener<V> = ((v: V) => void) | (() => void)
|
||
|
|
|
||
|
|
export default class Tappable<V> {
|
||
|
|
private _props: IProps<V>
|
||
|
|
private _tappers: Map<number, {bivarianceHack(v: V): void}['bivarianceHack']>
|
||
|
|
private _untapFromSource: null | UntapFromSource
|
||
|
|
private _lastTapperId: number
|
||
|
|
private _untapFromSourceTimeout: null | NodeJS.Timer = null
|
||
|
|
|
||
|
|
constructor(props: IProps<V>) {
|
||
|
|
this._lastTapperId = 0
|
||
|
|
this._untapFromSource = null
|
||
|
|
this._props = props
|
||
|
|
this._tappers = new Map()
|
||
|
|
}
|
||
|
|
|
||
|
|
private _check() {
|
||
|
|
if (this._untapFromSource) {
|
||
|
|
if (this._tappers.size === 0) {
|
||
|
|
this._scheduleToUntapFromSource()
|
||
|
|
/*
|
||
|
|
* this._untapFromSource()
|
||
|
|
* this._untapFromSource = null
|
||
|
|
*/
|
||
|
|
}
|
||
|
|
} else {
|
||
|
|
if (this._tappers.size !== 0) {
|
||
|
|
this._untapFromSource = this._props.tapToSource(this._cb)
|
||
|
|
}
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
private _scheduleToUntapFromSource() {
|
||
|
|
if (this._untapFromSourceTimeout !== null) return
|
||
|
|
this._untapFromSourceTimeout = setTimeout(() => {
|
||
|
|
this._untapFromSourceTimeout = null
|
||
|
|
if (this._tappers.size === 0) {
|
||
|
|
this._untapFromSource!()
|
||
|
|
|
||
|
|
this._untapFromSource = null
|
||
|
|
}
|
||
|
|
}, 0)
|
||
|
|
}
|
||
|
|
|
||
|
|
private _cb: any = (arg: any): void => {
|
||
|
|
this._tappers.forEach((cb) => {
|
||
|
|
cb(arg)
|
||
|
|
})
|
||
|
|
}
|
||
|
|
|
||
|
|
tap(cb: Listener<V>): Untap {
|
||
|
|
const tapperId = this._lastTapperId++
|
||
|
|
this._tappers.set(tapperId, cb)
|
||
|
|
this._check()
|
||
|
|
return () => {
|
||
|
|
this._removeTapperById(tapperId)
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
/*
|
||
|
|
* tapImmediate(cb: Listener<V>): Untap {
|
||
|
|
* const ret = this.tap(cb)
|
||
|
|
* return ret
|
||
|
|
* }
|
||
|
|
*/
|
||
|
|
|
||
|
|
private _removeTapperById(id: number) {
|
||
|
|
this._tappers.delete(id)
|
||
|
|
this._check()
|
||
|
|
}
|
||
|
|
|
||
|
|
// /**
|
||
|
|
// * @deprecated
|
||
|
|
// */
|
||
|
|
// map<T>(transform: {bivarianceHack(v: V): T}['bivarianceHack']): Tappable<T> {
|
||
|
|
// return new Tappable({
|
||
|
|
// tapToSource: (cb: (v: T) => void) => {
|
||
|
|
// return this.tap((v: $IntentionalAny) => {
|
||
|
|
// return cb(transform(v))
|
||
|
|
// })
|
||
|
|
// },
|
||
|
|
// })
|
||
|
|
// }
|
||
|
|
}
|