js使用List，在指定数据前面插入数据

﹏ヽ暗。殇╰゛Y 2022-05-18 23:26 484阅读 0赞

<!DOCTYPE html>
    <html lang="en">
    <head>
        <meta charset="UTF-8">
        <title>列表</title>
    </head>
    <body>
    
    </body>
    
    
    <script>
        function List() {
            this.dataStore = [];
            this.append = function (data) {
                //根据当前数组的长度插入新的数据
                this.dataStore[this.length()] = data;
            }
    
            this.length = function () {
                //获得数组的长度
                var length = this.dataStore.length;
                return length;
            }
    
            //如果找到当前的数据，就返回当前数据的下标，如果没有找到数据就返回-1
            this.find = function (data) {
                //1,获得数组的长度
                var length = this.length();
                //2,设置返回数据的下标
                var index = -1;
                //3,遍历数据
                for (var i = 0; i < length; i++) {
                    if (data == this.dataStore[i]) {
                        index = i;
                        return index;
                    }
                }
                return index;
            }
    
            this.forEach = function (call) {
                //1,获得数组的长度
                var length = this.length();
                //2,遍历数据
                for (var i = 0; i < length; i++) {
                    call(this.dataStore[i]);
                }
            }
    
            //在before前面插入数据,如果before有数据，就插入在before前面，如果before没有数据，就把data插入到最前面的数据
            this.insertBefore = function (data,before) {
                //1，找到当前before数据的下标
                var index = this.find(before);
                var length = this.length();
                if(index==-1) {
                    for (var i = length - 1; i >= 0; i--) {
                        this.dataStore[i + 1] = this.dataStore[i]
                    }
                    this.dataStore[0] = data;
                }
                else {
                    for (var i = length - 1; i >= index; i--) {
                        this.dataStore[i + 1] = this.dataStore[i]
                    }
                    this.dataStore[index] = data;
                }
            }
        }
    
        var list = new List();
        list.append(1);
        list.append(2);
        list.append(0);
        list.append(10);
        list.append(9);
    
        list.insertBefore("在2之前插入数据",2);
    
        list.forEach(function (data) {
            console.log(data);
        });
    
    
    </script>
    </html>