Stack data structure in javaScript.

algorithm.DS.stack-arr-noPushPop-impl.js

function Stack() {
    // this._size = 0;
    // this._storage = {};
    this._storage = []; // array could be more performant due to array browser optimize
}

Stack.prototype.push = function (data) {
    // var size = ++this._size;
    var len = this._storage.length;
    this._storage[len] = data;
};

Stack.prototype.peek = function () {
    var len = this._storage.length;
    return this._storage[len-1];
};

Stack.prototype.clear = function () {
    this._storage.length = 0;
};

Stack.prototype.pop = function () {
    var len = this._storage.length,
        deletedData;

    if (len > 0) {
        deletedData = this._storage[this._storage.length--];

        // delete this._storage[size];
        // this._storage[size] = null; // set to null clear mem than delete.
        // this._size--;

        return deletedData;
    }
};

algorithm.DS.stack-arr-pushpop-impl.js

var stack = [];

// first in
stack.push("a");
stack.push("b");

// last out
stack.pop(); // "b"

algorithm.DS.stack-linkList-impl.js

var Stack = function () {
    this.top = null;
    this.size = 0;
};

var Node = function (data) {
    this.data = data;
    this.previous = null;
};

Stack.prototype.push = function (data) {
    var node = new Node(data);

    node.previous = this.top;
    this.top = node;
    this.size += 1;
    return this.top;
};

Stack.prototype.pop = function () {
    temp = this.top;
    this.top = this.top.previous;
    this.size -= 1;
    return temp;
};