/**
 * @file 串行操作
 */

import type { Timeout } from '../types/type'

/**
 * 串行操作，将一组函数依次调用
 * 
 * @param actions 函数数组
 * @param interval 间隔时间
 * @returns 中断函数
 */
export default function serial(actions: Function[], interval: number): Function {
  let index = 0
  let timer: Timeout
  const handle = () => {
    if (actions[index]) {
      actions[index]()
      timer = setTimeout(
        function () {
          timer = null
          index++
          handle()
        },
        interval
      )
    }
  }
  handle()
  return () => {
    if (timer) {
      clearTimeout(timer)
    }
  }
}