列表方法的底层实现

秒速五厘米 2022-05-19 01:40 188阅读 0赞

<!DOCTYPE html>
    <html lang="en">
    <head>
        <meta charset="UTF-8">
        <title>Title</title>
    </head>
    <body>
    
    </body>
    <script>
        function List() {
            this.dataStore = [];
    
            this.append = function () {
                this.dataStore[this.length()] = data;
            }
    
            this.length = function () {
                //获取数组的长度
                var length = this.dataStore.length;
                return length;
            }
    
            this.find = function (data) {
                //获得数组的长度
                var length = this.length();
                //设置返回数组的下标
                var index = -1;
                //遍历
                for(var i=0;i<length;i++) {
                    if(data==this.dataStore[i]){
                        index = i
                        return index;
                    }
                }
                return index;
            }
    
            this.ForEach = function (call) {
                //获得数组的长度
                var length = this.length();
                //遍历
                for(var i=0;i<length;i++) {
                    call(this.dataStore[i]);
                }
            }
    
            //如果删除成功返回1，失败返回0
            this.remove = function (data) {
                //找到数据所在的位置
                var index = this.find(data);
                if(index==-1)
                    return 0;
                //获得数组的长度
                var length = this.length();
                for(var i=index+1;i<length;i++) {
                    this.dataStore[i-1] = this.dataStore[i];
                }
                this.dataStore[length-1] = null;
                this.dataStore.length--;
                return 1;
            }
    
            this.insert = function (data,after) {
                var index = this.find(after);
                if(index==-1) {
                    //向队列后面添加数据
                    this.append(data);
                }
                else {
                    var length = this.length();
                    for(var i=length-1;i>index;i--) {
                        this.dataStore[i] = this.dataStore[i+1];
                    }
                    this.dataStore[index+1] = data;
                }
            }
    
            this.clear = function () {
                delete this.dataStore;
                this.dataStore = [];
            }
    
            this.contains = function (data) {
    
                var iscontains = false;
                this.dataStore.forEach(function (item) {
                    if(item == data) {
                        iscontains = true;
                        return;
                    }
                });
                return iscontains;
            }
    
        }
    
        var list = new List();
    
        list.append(1);
        list.append(2);
        list.append(3);
        list.append(4);
    
        list.ForEach(function (data) {
            console.log(data);
        });
    
    </script>
    </html>