feature:增加append函数，打印查找操作忽略head指向的元素

javascript/06_linkedlist/SinglyLinkedList.js

@@ -15,7 +15,7 @@ class LinkedList {
   }
   // 根据value查找节点
   findByValue (item) {
-    let currentNode = this.head
+    let currentNode = this.head.next
     while (currentNode !== null && currentNode.element !== item) {
       currentNode = currentNode.next
     }
@@ -23,9 +23,9 @@ class LinkedList {
     return currentNode === null ? -1 : currentNode
   } 
   
-  // 根据index查找节点
+  // 根据index查找节点，下标从0开始
   findByIndex (index) {
-    let currentNode = this.head
+    let currentNode = this.head.next
     let pos = 0
     while (currentNode !== null && pos !== index) {
       currentNode = currentNode.next
@@ -35,6 +35,16 @@ class LinkedList {
     return currentNode === null ? -1 : currentNode
   }
 
+  // 向链表末尾追加节点
+  append(newElement) {
+    const newNode = new Node(newElement)
+    let currentNode = this.head
+    while(currentNode.next) {
+      currentNode = currentNode.next
+    }
+    currentNode.next = newNode
+  }
+  
   // 指定元素向后插入
   insert (newElement, element) {
     const currentNode = this.findByValue(element)
@@ -71,7 +81,7 @@ class LinkedList {
   
   // 遍历显示所有节点
   display () {
-    let currentNode = this.head
+    let currentNode = this.head.next
     while (currentNode !== null) {
       console.log(currentNode.element)
       currentNode = currentNode.next
@@ -80,10 +90,14 @@ class LinkedList {
 }
 // Test
 const LList = new LinkedList()
-LList.insert('chen', 'head')
-LList.insert('curry', 'chen')
-LList.insert('sang', 'head')
-LList.insert('zhao', 'head')
+LList.append('chen')
+LList.append('curry')
+LList.append('sang')
+LList.append('zhao') // chen -> curry -> sang -> zhao
+console.log('-------------insert item------------')
+LList.insert('qian', 'chen') // 首元素后插入
+LList.insert('zhou', 'zhao') // 尾元素后插入
+LList.display() // chen -> qian -> curry -> sang -> zhao -> zhou
 console.log('-------------remove item------------')
 LList.remove('curry')
 LList.display()