javascript - 从文件导出类时，Instance的类方法未定义(Class methods undefined for Instance when class is exported from file [closed])

Question

I have a class BinarySearchTree in a file ( a.js ) which I've exported then imported BinarySearchTree in other file and use it as a parent class for one of other class Traversal .(我在导出的文件（ a.js ）中有一个BinarySearchTree类，然后在其他文件中导入BinarySearchTree并将其用作其他类Traversal的父类。)

The issue, I felt is that the method present in the parent class is not accessible in the child class (throws error as :(我感到的问题是，父类中存在的方法无法在子类中访问（引发错误为：) error TS2339: Property 'getRootNode' does not exist on type 'Traversal'.(错误TS2339：类型“ Traversal”上不存在属性“ getRootNode”。) Note: I tried keeping both the class in the same file and it works without error.(注意：我尝试将两个类都放在同一文件中，并且可以正常工作。) I'm new to Typescript but well versed with ES Standards.(我是Typescript的新手，但精通ES标准。) Please highlight, If i'm missing any details here or if there is a work around.(请突出显示，如果我在这里缺少任何详细信息或有解决方法。) Code Segment: a.ts(代码段： a.ts) export class BinarySearchTree { root: any; constructor() { // root of a binary seach tree this.root = null; } getRootNode() { return this.root; } } b.ts(b.ts) import { BinarySearchTree } from './a.ts'; export class Traversal extends BinarySearchTree{ constructor() { super() } } var _traversal = new Traversal(); _traversal.getRootNode()   ask by SJC translate from so

Answer 1

try this(尝试这个)

constructor() { this.data = 123; this.testMethod = this.testMethod.bind(this); } testMethod() { console.log('test') } Now you have access to testMethod() of this class.(现在，您可以访问此类的testMethod（）。) As you can see I just created a property instance named testMethod which represents testMethod() in the current class.(如您所见，我刚刚创建了一个名为testMethod的属性实例，该实例表示当前类中的testMethod() 。) Since this pointer refers to encapsulated class that is why you can access to its members.(由于this指针指向封装的类，因此您可以访问其成员。)