没有数组(年代)

//Javascript stack linked list data structure (no array)

function node(value, noderef) {
    this.value = value;
    this.next = noderef;
}
function stack() {
    this.push = function (value) {
        this.next = this.first;
        this.first = new node(value, this.next);
    }
    this.pop = function () {
        var popvalue = this.first.value;
        this.first = this.first.next;
        return popvalue;
    }
    this.hasnext = function () {
        return this.next != undefined;
    }
    this.isempty = function () {
        return this.first == undefined;
    }

}

//Javascript stack linked list data structure (no array)
function node(value, noderef) {
    this.value = value;
    this.next = undefined;
}
function queue() {
    this.enqueue = function (value) {
        this.oldlast = this.last;
        this.last = new node(value);
        if (this.isempty())
            this.first = this.last;
        else 
           this.oldlast.next = this.last;
    }
    this.dequeue = function () {
        var queuvalue = this.first.value;
        this.first = this.first.next;
        return queuvalue;
    }
    this.hasnext = function () {
        return this.first.next != undefined;
    }
    this.isempty = function () {
        return this.first == undefined;
    }

}

如果有人需要它，你可以使用这个NPM包https://www.npmjs.com/package/data-structures-typescript，它有一个队列和堆栈，它支持javascript和typescript，它是通用的，所以你可以用你自己的值类型;)

很抱歉碰到这个话题，但我滚动了许多答案，没有看到任何基于对象的队列的实现，它可以用O(1)执行排队和出队列，并且没有浪费内存。

Dmitri Pavlutin在他的博客https://dmitripavlutin.com/javascript-queue/上有一个很好的入门代码

它只遗漏了一个长度为0的检查，这是很容易添加的。

这个解决方案的最大和唯一的问题是不断增长的索引可能会在某一点上达到一些数量限制，如果队列运行很长时间和/或高速(我的意图是处理音频=高速)。

这个问题没有完美的解决方案……最简单的方法是在队列为空时将索引重置为0。

最后，我添加了一个重构方法，它将所有索引移回开始，以在队列永远不为空的情况下使用。

性能无疑是更好的(以毫秒为单位的时间，排队10000个号码然后退出它们):

class QueueObject {
  constructor () {
    this.data = {}
    this.head = 0
    this.tail = 0
    this.length = 0
  }
  enqueue (value) {
    this.data[this.tail++] = value
    this.length++
  }
  dequeue () {
    let value
    if (this.length > 0) {
      this.length--
      value = this.data[this.head]
      delete this.data[this.head++]
    } else {
      this.head = 0
      this.tail = 0
      value = null
    }
    return value
  }
  refactor () {
    if (this.head > 0) {
      for (let i = this.head; i < this.tail; i++) {
        this.data[i - this.head] = this.data[i]
        delete this.data[i]
      }
      this.tail = this.length
      this.head = 0
    }
  }
}

var stack = [];
stack.push(2);       // stack is now [2]
stack.push(5);       // stack is now [2, 5]
var i = stack.pop(); // stack is now [2]
alert(i);            // displays 5

var queue = [];
queue.push(2);         // queue is now [2]
queue.push(5);         // queue is now [2, 5]
var i = queue.shift(); // queue is now [5]
alert(i);              // displays 2

摘自“9个你可能不知道的JavaScript技巧”

有很多方法可以在Javascript中实现堆栈和队列。上面的大多数答案都是非常肤浅的实现，我将尝试实现一些更可读(使用es6的新语法特性)和更健壮的东西。

下面是堆栈实现:

class Stack {
  constructor(...items){
    this._items = []

    if(items.length>0)
      items.forEach(item => this._items.push(item) )

  }

  push(...items){
    //push item to the stack
     items.forEach(item => this._items.push(item) )
     return this._items;

  }

  pop(count=0){
    //pull out the topmost item (last item) from stack
    if(count===0)
      return this._items.pop()
     else
       return this._items.splice( -count, count )
  }

  peek(){
    // see what's the last item in stack
    return this._items[this._items.length-1]
  }

  size(){
    //no. of items in stack
    return this._items.length
  }

  isEmpty(){
    // return whether the stack is empty or not
    return this._items.length==0
  }

  toArray(){
    return this._items;
  }
}

下面是如何使用堆栈:

let my_stack = new Stack(1,24,4);
// [1, 24, 4]
my_stack.push(23)
//[1, 24, 4, 23]
my_stack.push(1,2,342);
//[1, 24, 4, 23, 1, 2, 342]
my_stack.pop();
//[1, 24, 4, 23, 1, 2]
my_stack.pop(3)
//[1, 24, 4]
my_stack.isEmpty()
// false
my_stack.size();
//3

如果您想查看关于此实现的详细描述以及如何进一步改进，请阅读这里:http://jschap.com/data-structures-in-javascript-stack/

下面是es6中队列实现的代码:

class Queue{
 constructor(...items){
   //initialize the items in queue
   this._items = []
   // enqueuing the items passed to the constructor
   this.enqueue(...items)
 }

  enqueue(...items){
    //push items into the queue
    items.forEach( item => this._items.push(item) )
    return this._items;
  }

  dequeue(count=1){
    //pull out the first item from the queue
    this._items.splice(0,count);
    return this._items;
  }

  peek(){
    //peek at the first item from the queue
    return this._items[0]
  }

  size(){
    //get the length of queue
    return this._items.length
  }

  isEmpty(){
    //find whether the queue is empty or no
    return this._items.length===0
  }
}

下面是如何使用这个实现:

let my_queue = new Queue(1,24,4);
// [1, 24, 4]
my_queue.enqueue(23)
//[1, 24, 4, 23]
my_queue.enqueue(1,2,342);
//[1, 24, 4, 23, 1, 2, 342]
my_queue.dequeue();
//[24, 4, 23, 1, 2, 342]
my_queue.dequeue(3)
//[1, 2, 342]
my_queue.isEmpty()
// false
my_queue.size();
//3

要完整地了解如何实现这些数据结构以及如何进一步改进这些数据结构，您可能需要阅读jschap.com上的“在javascript中处理数据结构”系列。这是队列的链接——http://jschap.com/playing-data-structures-javascript-queues/

As many have said: native array using push and pop is fine for a stack, but using shift for taking elements from a queue means that the remaining elements need to move, which is potentially slow. The idea of using two stacks to make a queue in kevinyu's answer is a nice idea to fix it, and of course that can be done with native-array-stacks as well. (Edit: there was actually already an answer by Yuki-Dreamer that does this, albeit less compactly. I didn't notice it until now because it was unfairly downvoted.)

下面是一个使用ES5/ES6特性的紧凑实现，它使队列对象的行为尽可能接近本机的push/shift变体，除了每次操作花费O(1)平摊时间:

const queue = () => {
    const a = [], b = [];
    return {
        push: (...elts) => a.push(...elts),
        shift: () => {
            if (b.length === 0) {
                while (a.length > 0) { b.push(a.pop()) }
            }
            return b.pop();
        },
        get length() { return a.length + b.length }
    }
}

现在你可以做:

const q = queue();
q.push(8);
q.push(9);
q.push(10);
console.log(q.length);          // outputs 3
console.log(q.shift());         // outputs 8
q.push(11);
console.log(q.shift());         // outputs 9
console.log(q.shift());         // outputs 10
console.log(q.shift());         // outputs 11
console.log(q.shift());         // outputs undefined

队列实现对长度使用getter语法，使其看起来像一个属性，并对push使用rest参数语法，以允许一次推送多个内容。如果你不想这样做，你可以用push: elt => a.push(elt)，替换第4行。(但是请注意，你不能用push: a.push替换它，就像我自己第一次尝试的那样，结果非常奇怪:这是因为它导致本机push方法被调用，并设置为队列对象。)