Conversion of module.exports from javascript to typescript

Question

I have Node-express code where modules are exported by using module.exports. For example, to export a function, it is written module.exports = functionName. Now the code will be converted to typescript. How to replace module.exports in typescript?

Answer 1

Just use export followed by the typical declaration, no matter whether it is a const , function , interface , enum , you name it.

export const myTestConst = () => console.log('hello world');

See https://www.typescriptlang.org/docs/handbook/modules.html

Answer 2

Adding up to duschsocke answer. You can also create a class with public methods and importing that class where you need those methods.

utils.ts

class Utils {

  public static publicFunction() {
    console.log('calling me');
  }
}

On other ts file:

import * as utils from 'utils';

// Call the function
utils.publicFunction(); // Prints 'calling me' on console.

Answer 3

In a module module.js, we could include the following code:

// module "my-module.js"
function cube(x) {
  return x * x * x;
}

const foo = Math.PI + Math.SQRT2;

var graph = {
  options: {
      color:'white',
      thickness:'2px'
  },
  draw: function() {
      console.log('From graph draw function');
  }
}

export { cube, foo, graph };

Then in the top-level module included in your HTML page, we could have:

import { cube, foo, graph } from 'my-module.js';

graph.options = {
    color:'blue',
    thickness:'3px'
};

graph.draw();
console.log(cube(3)); // 27
console.log(foo);    // 4.555806215962888

Using the default export

If we want to export a single value or to have a fallback value for your module, you could use a default export:

// module "my-module.js"

export default function cube(x) {
  return x * x * x;
}

Then, in another script, it is straightforward to import the default export:

import cube from './my-module.js';
console.log(cube(3)); // 27

Answer 4

在TypeScript中，使用export = functionName 。