Remove Tappable and Emitter
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Aria Minaei
parent
391958f5cf
commit
867cf51acb
4 changed files with 1 additions and 188 deletions
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@ -254,7 +254,7 @@ class PrismInstance<V> implements Prism<V> {
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}
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/**
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* Returns a tappable that fires every time the prism's state goes from `fresh-\>stale.`
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* Calls `callback` every time the prism's state goes from `fresh-\>stale.` Returns an `unsubscribe()` function.
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*/
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onStale(callback: () => void): VoidFn {
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const untap = () => {
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@ -1,19 +0,0 @@
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import Emitter from './Emitter'
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describe('DataVerse.Emitter', () => {
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it('should work', () => {
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const e: Emitter<string> = new Emitter()
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e.emit('no one will see this')
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e.emit('nor this')
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const tappedEvents: string[] = []
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const untap = e.tappable.tap((payload) => {
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tappedEvents.push(payload)
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})
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e.emit('foo')
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e.emit('bar')
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untap()
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e.emit('baz')
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expect(tappedEvents).toMatchObject(['foo', 'bar'])
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})
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})
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@ -1,76 +0,0 @@
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import Tappable from './Tappable'
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type Tapper<V> = (v: V) => void
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type Untap = () => void
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/**
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* An event emitter. Emit events that others can tap (subscribe to).
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*/
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export default class Emitter<V> {
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private _tappers: Map<any, (v: V) => void>
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private _lastTapperId: number
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private _onNumberOfTappersChangeListener: undefined | ((n: number) => void)
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/**
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* The Tappable associated with this emitter. You can use this to tap (subscribe to) events emitted.
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*/
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readonly tappable: Tappable<V>
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constructor() {
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this._lastTapperId = 0
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this._tappers = new Map()
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this.tappable = new Tappable({
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tapToSource: (cb: Tapper<V>) => this._tap(cb),
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})
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}
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_tap(cb: Tapper<V>): Untap {
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const tapperId = this._lastTapperId++
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this._tappers.set(tapperId, cb)
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this._onNumberOfTappersChangeListener?.(this._tappers.size)
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return () => {
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this._removeTapperById(tapperId)
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}
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}
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_removeTapperById(id: number) {
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const oldSize = this._tappers.size
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this._tappers.delete(id)
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const newSize = this._tappers.size
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if (oldSize !== newSize) {
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this._onNumberOfTappersChangeListener?.(newSize)
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}
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}
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/**
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* Emit a value.
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*
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* @param payload - The value to be emitted.
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*/
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emit(payload: V) {
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for (const cb of this._tappers.values()) {
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cb(payload)
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}
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}
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/**
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* Checks whether the emitter has tappers (subscribers).
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*/
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hasTappers() {
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return this._tappers.size !== 0
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}
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/**
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* Calls callback when the number of tappers (subscribers) changes.
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*
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* @example
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* ```ts
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* emitter.onNumberOfTappersChange((n) => {
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* console.log("number of tappers changed:", n)
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* })
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* ```
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*/
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onNumberOfTappersChange(cb: (n: number) => void) {
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this._onNumberOfTappersChangeListener = cb
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}
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}
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@ -1,92 +0,0 @@
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type Untap = () => void
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type UntapFromSource = () => void
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interface IProps<V> {
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tapToSource: (cb: (payload: V) => void) => UntapFromSource
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}
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type Listener<V> = ((v: V) => void) | (() => void)
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/**
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* Represents a data-source that can be tapped (subscribed to).
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*/
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export default class Tappable<V> {
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private _props: IProps<V>
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private _tappers: Map<number, {bivarianceHack(v: V): void}['bivarianceHack']>
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private _untapFromSource: null | UntapFromSource
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private _lastTapperId: number
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private _untapFromSourceTimeout: null | NodeJS.Timer = null
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constructor(props: IProps<V>) {
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this._lastTapperId = 0
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this._untapFromSource = null
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this._props = props
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this._tappers = new Map()
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}
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private _check() {
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if (this._untapFromSource) {
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if (this._tappers.size === 0) {
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this._scheduleToUntapFromSource()
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/*
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* this._untapFromSource()
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* this._untapFromSource = null
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*/
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}
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} else {
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if (this._tappers.size !== 0) {
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this._untapFromSource = this._props.tapToSource(this._cb)
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}
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}
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}
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private _scheduleToUntapFromSource() {
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if (this._untapFromSourceTimeout !== null) return
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this._untapFromSourceTimeout = setTimeout(() => {
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this._untapFromSourceTimeout = null
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if (this._tappers.size === 0) {
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this._untapFromSource!()
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this._untapFromSource = null
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}
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}, 0)
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}
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private _cb: any = (arg: any): void => {
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for (const cb of this._tappers.values()) {
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cb(arg)
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}
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}
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/**
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* Tap (subscribe to) the data source.
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*
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* @param cb - The callback to be called on a change.
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*/
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tap(cb: Listener<V>): Untap {
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const tapperId = this._lastTapperId++
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this._tappers.set(tapperId, cb)
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this._check()
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return () => {
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this._removeTapperById(tapperId)
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}
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}
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private _removeTapperById(id: number) {
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this._tappers.delete(id)
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this._check()
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}
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// /**
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// * @deprecated
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// */
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// map<T>(transform: {bivarianceHack(v: V): T}['bivarianceHack']): Tappable<T> {
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// return new Tappable({
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// tapToSource: (cb: (v: T) => void) => {
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// return this.tap((v: $IntentionalAny) => {
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// return cb(transform(v))
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// })
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// },
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// })
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// }
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}
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