栈的实现

 //栈的实现
    function Stack() {
        this.dataStore = [];//初始化数组
        this.top = 0;//记录栈顶位置
        this.push = push;//入栈
        this.pop = pop;//出栈
        this.peek = peek;//栈顶元素
        this.length = length;//栈内元素
        this.clear = clear;//清空
    }
 
    //入栈
    function push(element) {
        this.dataStore[this.top++] = element;
    }
 
    //出栈
    function pop() {
        return this.dataStore[--this.top];
    }
 
    //栈顶元素
    function peek() {
        return this.dataStore[this.top - 1];
    }
 
    //栈内元素大小
    function length() {
        return this.top;
    }
    
    //清空
    function clear() {
        delete this.dataStore;
        this.dataStore = [];
        this.top = 0;
    }
    var s = new Stack();
    s.push("a");
    s.push("b");
    s.push('c');
    s.push('d');

/// <summary>
/// 数组去重
/// </summary>
/// <param name="fieldName">去重的字段名</param> 
Array.prototype.distinct = function (fieldName) {
    var arr = this;
    var uniqueArr = [];
    var includedKey = {};
    for (var i = 0; i < arr.length; i++) {
        var value = arr[i][fieldName];
        if (includedKey[value]) continue;
        uniqueArr.push(arr[i]);
        includedKey[value] = 1;
    }
    return uniqueArr;
}
// 测试
var test = [{ id: '1' }, { id: '2' }, { id: '2' }, { id: '1' }, { id: '3' }];
test = test.distinct('id');
alert(JSON.stringify(test));