PeerTube/server/helpers/promise-cache.ts
2021-06-09 13:34:40 +02:00

22 lines
456 B
TypeScript

export class PromiseCache <A, R> {
private readonly running = new Map<string, Promise<R>>()
constructor (
private readonly fn: (arg: A) => Promise<R>,
private readonly keyBuilder: (arg: A) => string
) {
}
run (arg: A) {
const key = this.keyBuilder(arg)
if (this.running.has(key)) return this.running.get(key)
const p = this.fn(arg)
this.running.set(key, p)
return p.finally(() => this.running.delete(key))
}
}