Function sequential

source code/utils/sequential.ts:21–58

(
  fn: (...args: T) => Promise<R>,
)

 * @returns A wrapped version of the function that executes calls sequentially
 */
export function sequential<T extends unknown[], R>(
  fn: (...args: T) => Promise<R>,
): (...args: T) => Promise<R> {
  const queue: QueueItem<T, R>[] = []
  let processing = false

  async function processQueue(): Promise<void> {
    if (processing) return
    if (queue.length === 0) return

    processing = true

    while (queue.length > 0) {
      const { args, resolve, reject, context } = queue.shift()!

      try {
        const result = await fn.apply(context, args)
        resolve(result)
      } catch (error) {
        reject(error)
      }
    }

    processing = false

    // Check if new items were added while we were processing
    if (queue.length > 0) {
      void processQueue()
    }
  }

  return function (this: unknown, ...args: T): Promise<R> {
    return new Promise((resolve, reject) => {
      queue.push({ args, resolve, reject, context: this })
      void processQueue()
    })
  }
}