js 링크 조작 실현

//             
function Node(v) {
     
    this.val = v;
    this.next = null;
}
function ArrayList() {
     
    //         
    this.head = new Node(null);
    //       ，               
    this.tail = this.head;
    //             
    this.append = function (v) {
     
        let node = new Node(v);
        this.tail.next = node;
        //  this.tail               
        this.tail = node;
    };
    //   no            
    this.insertAt = function (no, v) {
     
        let node = new Node(v);
        let tempNode = this.head;
        for (let i = 0; i < no; i++) {
     
            if (tempNode.next) {
     
                tempNode = tempNode.next;
            } else {
     
                break;
            }
        }
        node.next = tempNode.next;
        tempNode.next = node;
    };
    // no               
    this.removeAt = function (no) {
     
        let tempNode = this.head;
        for (let i = 0; i < no; i++) {
     
            if (tempNode.next) {
     
                tempNode = tempNode.next;
            } else {
     
                break;
            }
        }
        //          node2
        let node2 = tempNode.next;
        if (node2) {
     
            //     
            tempNode.next = node2.next;
            if (node2.next == null) {
     
                //         next null                       
                this.tail = tempNode;
            }
        }
    };
}
function Iterator(arrayList) {
     
    //         
    this.point = arrayList.head;
    //                ，                   true，    false
    this.hasNext = function () {
     
        if (this.point.next) {
     
            this.point = this.point.next;
            return true;
        } else {
     
            return false;
        }
    };
    //          
    this.next = function () {
     
        return this.point.val;
    }
}
var arry = new ArrayList();
arry.append(1);
arry.append(2);
arry.append(3);
arry.insertAt(1, 8);
arry.insertAt(0, 9);
arry.insertAt(100, 100);
arry.insertAt(1000, 1000);
arry.insertAt(1, 200);
arry.insertAt(200, 2000);
iterator = new Iterator(arry);
while (iterator.hasNext()) {
     
    document.write(iterator.next());
    document.write('
');
}