[github/Chocobozzz/PeerTube.git] / server / helpers / promise-cache.ts

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))
  }
}
Commit	Line	Data
4ead40e7 C	1	export class PromiseCache <A, R> {
	2	private readonly running = new Map<string, Promise<R>>()
	3
	4	constructor (
	5	private readonly fn: (arg: A) => Promise<R>,
	6	private readonly keyBuilder: (arg: A) => string
	7	) {
	8	}
	9
	10	run (arg: A) {
	11	const key = this.keyBuilder(arg)
	12
	13	if (this.running.has(key)) return this.running.get(key)
	14
	15	const p = this.fn(arg)
	16
	17	this.running.set(key, p)
	18
	19	return p.finally(() => this.running.delete(key))
	20	}
	21	}