Deque

Deques are a generalization of stacks and queues (the name is pronounced "deck" and is short for "double-ended queue"). -- Python collections.

Installation

npm install @blakeembrey/deque --save

Usage

size Returns the number of elements in the deque.
push(x) Add x to right side of the deque.
pushLeft(x) Add x to the left side of the deque.
clear() Remove all elements from the deque leaving it with length 0.
extend(iterable) Extend the right side of the deque by appending elements from iterable.
extendLeft(iterable) Extend the left side of the deque by appending elements from iterable.
peek(i) Return the element at index i in the deque.
indexOf(x, start?) Return the position of x in the deque.
has(x) Return a boolean indicating whether x is in the deque.
insert(i, x) Insert x into the deque at position i.
pop() Remove and return an element from the right side of the deque. If no elements are present, throws RangeError.
popLeft() Return and return an element from the left side of the deque. If no elements are present, throws RangeError.
delete(i) Delete the value at position i.
reverse() Reverse the elements of the deque in-place.
rotate(n=1) Rotate the deque n steps to the right.
entries() Return an iterable of deque.
@@iterator() Return an iterable of deque.

import { Deque } from '@blakeembrey/deque'

const d = new Deque('ghi')

for (const value of d) {
  console.log(value.toUpperCase()) //=> G H I
}

d.push('j')
d.pushLeft('f')
d //=> Deque(['f', 'g', 'h', 'i', 'j'])

d.pop() //=> 'j'
d.popLeft() //=> 'f'

Array.from(d) //=> ['g', 'h', 'i']

d.peek(0) //=> 'g'
d.peek(-1) //=> 'i'

d.extend('jkl')
d //=> Deque(['g', 'h', 'i', 'j', 'k', 'l'])

d.rotate(1)
d //=> Deque(['l', 'g', 'h', 'i', 'j', 'k'])

d.rotate(-1)
d //=> Deque(['g', 'h', 'i', 'j', 'k', 'l'])

const d2 = new Deque(d)

d2 //=> Deque(['g', 'h', 'i', 'j', 'k', 'l'])

TypeScript

This project uses TypeScript and publishes definitions on NPM.

Reference

Circular array implementation originally based on denque with additional optimizations.

License

Apache 2.0