62 lines
1.2 KiB
TypeScript
62 lines
1.2 KiB
TypeScript
import { logger } from "@coder/logger"
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/**
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* Event emitter callback. Called with the emitted value and a promise that
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* resolves when all emitters have finished.
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*/
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export type Callback<T, R = void | Promise<void>> = (t: T, p: Promise<void>) => R
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export interface Disposable {
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dispose(): void
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}
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export interface Event<T> {
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(listener: Callback<T>): Disposable
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}
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/**
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* Emitter typecasts for a single event type.
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*/
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export class Emitter<T> {
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private listeners: Array<Callback<T>> = []
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public get event(): Event<T> {
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return (cb: Callback<T>): Disposable => {
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this.listeners.push(cb)
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return {
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dispose: (): void => {
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const i = this.listeners.indexOf(cb)
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if (i !== -1) {
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this.listeners.splice(i, 1)
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}
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},
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}
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}
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}
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/**
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* Emit an event with a value.
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*/
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public async emit(value: T): Promise<void> {
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let resolve: () => void
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const promise = new Promise<void>((r) => (resolve = r))
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await Promise.all(
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this.listeners.map(async (cb) => {
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try {
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await cb(value, promise)
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} catch (error) {
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logger.error(error.message)
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}
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}),
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)
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resolve!()
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}
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public dispose(): void {
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this.listeners = []
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}
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}
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