Function promiseMapPool

packages/@contentlayer/utils/src/promise.ts:23–43

(
  arr: T[],
  map: (el: T, index?: number) => Promise<Res>,
  poolLimit: number,
)

}

export const promiseMapPool = async <T, Res>(
  arr: T[],
  map: (el: T, index?: number) => Promise<Res>,
  poolLimit: number,
): Promise<Res[]> => {
  const ret: Promise<Res>[] = []
  const executing: Promise<Res>[] = []
  for (const [index, item] of arr.entries()) {
    const p = Promise.resolve().then(() => map(item, index))
    ret.push(p)

    if (poolLimit <= arr.length) {
      const e: any = p.then(() => executing.splice(executing.indexOf(e), 1))
      executing.push(e)
      if (executing.length >= poolLimit) {
        await Promise.race(executing)
      }
    }
  }
  return Promise.all(ret)
}