JS基于引用类型实现单链表与常用方法

function LinkArray() {
    // 实例属性
    this.head = null;           // 链表的头节点
    this.length = 0;            // 记录链表的长度
    // 内部函数
    function Node(data) {
        this.data = data;
        this.next = null;
    }

    // 定义原型方法
    LinkArray.prototype.append = function (data) {
        // 创建新结点
        var newNode = new Node(data);

        // 判断指针是否为NULL
        if (this.head == null) {
            this.head = newNode;
        }
        else {
            // 定义当前结点
            var current = this.head;
            // 循环找当前结点
            while (current.next) {
                current = current.next;
            }
            // 找到当前结点后，将其next指向newNode
            current.next = newNode;
        }
        this.length++;
    }

    LinkArray.prototype.toString = function () {
        var current = this.head;
        var string = "";
        while (current) {
            string += current.data;
            current = current.next;
        }
        return string;
    }

    LinkArray.prototype.insert = function (position, data) {
        // 创建元素
        var newNode = new Node(data);

        // 元素为空的情况
        if (this.head == null) {
            this.head = newNode;
            this.length++;
            return true;
        }
        // 边界判断
        if (position < 0 || position >= this.length) return false;

        /* 插入分为三种情况*/
        // 头插入
        if (position == 0) {
            var current = this.head;
            newNode.next = current;
            this.head = newNode;
        }

        // 尾插入
        else if (position == this.length - 1) {
            var current = this.head;
            while (current.next) {
                current = current.next;
            }
            current.next = newNode;
        }
        // 中间插入 找到要插入结点的前一个结点
        else {
            var current = this.head;
            var index = 0;
            while (index++ != position - 1) {
                current = current.next;
            }
            var temp = current.next;
            current.next = newNode;
            newNode.next = temp;
        }
        this.length++;
        return true;
    }

    LinkArray.prototype.get = function (position) {
        // 判断边界
        if (position < 0 || position >= this.length) return null;

        var current = this.head;
        while (position--) {
            current = current.next;
        }
        return current.data;
    }

    LinkArray.prototype.indexOf = function (data) {

        var current = this.head;

        var index = 0;
        while (current) {
            if (current.data == data) {
                return index;
            }
            current = current.next;
            index++;
        }
        return -1;

    }

    LinkArray.prototype.update = function (position, data) {
        if (position < 0 || position >= this.length) return false;

        var current = this.head;

        while (position--) {
            current = current.next;
        }

        current.data = data;

        return true;

    }

    LinkArray.prototype.removeAt = function (position) {
        if (position < 0 || position >= this.length) return false;

        var current = this.head;

        /* 删除分为3三种情况*/
        // 头删除
        if (position == 0) {
            this.head = current.next;
        }
        // 尾删除
        else if (position == this.length - 1) {
            while ((position--) > 1) {
                current = current.next;
            }
            current.next = null;
        }
        // 中间删除 思想：找到要删除元素的前一个，直接跨过当前元素 连接当前元素的下一个元素。
        else {
            var index = 0;
            while (index++ != position - 1) {
                current = current.next;
            }
            var temp = current.next;
            current.next = temp.next;
        }
        this.length--;
        return true;
    }

    LinkArray.prototype.remove = function (data) {
        var position = this.indexOf(data);
        return this.removeAt(position);
    }

    LinkArray.prototype.isEmpty = function () {
        return this.length == 0 ? true : false;
    }

    LinkArray.prototype.size = function () {
        return this.length;
    }
}

var l = new LinkArray();
l.insert(0, "123 ")
l.insert(0, "124 ")

console.log(l.toString());