Deprecated

The functionality in this module has been moved to the module abstract-data-types which now contains the Queue as well as other abstract data types. adt-queue will no longer be maintained.

Please go to https://www.npmjs.org/package/abstract-data-types.

adt-queue

This module implements the abstract data type Queue. All the standard Queue operations have been implemented. These are:

• create instantiates an empty queue
• enqueue adds a new item to the back of the queue
• dequeue returns the item at the front of the queue and removes it from the queue
• front returns the item at the front of the queue
• isEmpty determines whether the queue is empty and returns true if it is and false otherwise

Installation

$ npm install adt-queue

Getting Started

The constructor can be added to your code using the require statement.

var Queue = require('adt-queue');

Create

To create an empty queue simply instantiates and adt-queue object.

var q = new Queue();

Enqueue

The enqueue operation adds a new item to the back of the queue. To do this call the enqueue method on a Queue instance passing it the data item you wish to add to the Queue.

q.enqueue({data: 'item'});

Dequeue

The dequeue method returns the item at the front of the queue and removes that item from the queue. To do this call dequeue on a queue object.

var frontItem = q.dequeue();

If dequeue is called on an empty queue, the following error is thrown.

new Error('adt-queue.dequeue(): Tried to dequeue an empty queue!');

Front

The front method returns the item at the front of the queue, but unlike dequeue it does not remove it from the queue.

var frontItem = q.front();

If front is called on an empty queue, the following error is thrown.

new Error('adt-queue.front(): Tried to get the front of an empty queue!');

IsEmpty

The isEmpty method is a boolean function that, when called on a queue, returns true if the queue is empty and false otherwise.

q.isEmpty();