Typescript: how to import a class from a javascript file?

Question

I would like to :

• Import a js file that defines a class: ./myClass/index.js
• Declare the public methods of MyClass somewhere

Answer 1

There is no export default class in JavaScript. What you can do is write your JS file like this. myClass/index.js

"use strict";
class MyClass {
  hello(name) {
    console.log(`Hello ${name}`);
  }

}
exports.default = MyClass;

Create a Type definitions for it. myClass/index.d.ts

export default class MyClass {
  hello(name: string): void;
}

You can then import it into your TypeScript like this.

/// 
import MyClass from "./myClass";

const my = new MyClass();
my.hello("Stack Overflow");