-queue

README.md

Queue

npm i gist:b22ca12fcee4e1d4c3c0f85d43080f92

package.json

{
  "version": "0.0.3",
  "name": "queue",
  "main": "queue.js"
}

queue.js

'use strict'

class Queue {
  constructor () {
    this._arr = []
    this._i = 0
    this.size = 0
  }

  push (value) {
    this._arr.push(value)
    ++this.size
  }

  shift () {
    if (this.size === 0) return undefined

    const value = this._arr[this._i]
    this._arr[this._i] = undefined

    if (++this._i > --this.size) {
      this._arr = this._arr.slice(this._i)
      this._i = 0
    }

    return value
  }

  peek () {
    return this._arr[this._i]
  }
}

exports.Queue = Queue