Write a JavaScript Program to Implement a Queue

write-a-javascript-program-to-implement-a-queue

In JavaScript, a queue is a data structure that stores a collection of elements in a specific order.

The elements are added to the back of the queue, and they are removed from the front of the queue. The queue follows the First In First Out (FIFO) principle.

To implement a queue in JavaScript, we can use an array to store the elements and use the push() method to add elements to the back of the array and the shift() method to remove elements from the front of the array.

Here’s an example of how to implement a queue in JavaScript:

class Queue {
  constructor() {
    this.items = [];
  }

  enqueue(item) {
    this.items.push(item);
  }

  dequeue() {
    if (this.isEmpty()) {
      return null;
    }
    return this.items.shift();
  }

  front() {
    if (this.isEmpty()) {
      return null;
    }
    return this.items[0];
  }

  isEmpty() {
    return this.items.length === 0;
  }

  size() {
    return this.items.length;
  }
}

In the above example, we define a Queue class with the constructor method that initializes an empty array to store the elements.

The enqueue() method is used to add elements to the back of the queue. It does this by using the push() method to add the element to the end of the array.

The dequeue() method is used to remove elements from the front of the queue. It does this by using the shift() method to remove the first element from the array.

The front() method is used to get the element at the front of the queue without removing it. It does this by accessing the first element in the array.

The isEmpty() method is used to check if the queue is empty. It does this by checking if the length of the array is zero.

The size() method is used to get the number of elements in the queue. It does this by returning the length of the array.

Here’s an example of how to use the Queue class:

const q = new Queue();
q.enqueue(1);
q.enqueue(2);
q.enqueue(3);
console.log(q.front()); // output: 1
console.log(q.dequeue()); // output: 1
console.log(q.size()); // output: 2
console.log(q.isEmpty()); // output: false

In the above example, we create a new Queue object and add three elements to it using the enqueue() method.

We then get the element at the front of the queue using the front() method, remove the first element using the dequeue() method, get the number of elements in the queue using the size() method, and check if the queue is empty using the isEmpty() method.

In conclusion, implementing a queue in JavaScript is easy using an array and the push() and shift() methods.

The Queue class we defined above provides a convenient way to manage queues in JavaScript.

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