Task Queue

Design an API that processes objects sequentially (where each object must wait for the previous one to finish before executing), we can create a task queue. This queue will hold objects (representing tasks) and execute each one only after the previous task has completed.

API Design

class TaskQueue {

  queue = Promise.resolve()

  enqueue = (task) => {
    this.queue = this.queue.then(() => {
      console.log('Executing task...');
      return task()
    }).catch(e => {
      console.log(e.message);
    })
    return queue
  }
}


// Example tasks
function task1() {
  return new Promise(resolve => {
    setTimeout(() => {
      console.log("Task 1 completed");
      resolve();
    }, 1000);
  });
}

function task2() {
  return new Promise(resolve => {
    setTimeout(() => {
      console.log("Task 2 completed");
      resolve();
    }, 500);
  });
}

function task3() {
  return new Promise(resolve => {
    setTimeout(() => {
      console.log("Task 3 completed");
      resolve();
    }, 2000);
  });
}

// Create a task queue
const queue = new TaskQueue();

// Enqueue tasks
queue.enqueue(task1);
queue.enqueue(task2);
queue.enqueue(task3);

/* 
Executing task...
Task 1 completed
Executing task...
Task 2 completed
Executing task...
Task 3 completed
*/