Coding Practice: Implement AsyncTaskQueue

Question #

Design and implement an AsyncTaskQueue class that manages the execution of asynchronous tasks with a specified maximum concurrency limit. The queue should execute tasks in the order they are added (FIFO) and ensure that no more than the specified number of tasks run concurrently. If a task’s Promise rejects, the rejection should be silently ignored, allowing the queue to continue processing remaining tasks.

Solution #

class AsyncTaskQueue {
  constructor(concurrency) {
    this.concurrency = concurrency
    this.taskQueue = []
    this.runningCount = 0
  }

  async runTask(task) {
    try {
      await task()
    }
    catch (err) {
      // just continut
    }
    finally {
      this.runningCount--
      this.runNextTask()
    }
  }

  runNextTask() {
    if (this.runningCount < this.concurrency && this.taskQueue.length > 0) {
      const nextTask = this.taskQueue.shift()
      this.runningCount++
      this.runTask(nextTask)
    }
  }

  addTask(task) {
    this.taskQueue.push(task)
    this.runNextTask()
  }
}