This is a dumb project... which could make you win a lot of time ⏳ You are in the situation where:
-
You've got a legacy NodeJS project in Javascript
- tons of
module.exports🕸, - with tons of
require()🕸
- tons of
-
You want to improve by:
- switching to Typescript with allowJs ✨ (or by switching to Ts at once!)
- taking benefit of ES
importinterdependency fix unlike CommonJS
This script will (try to) handle all basic replacements to make a big change at once 🚀
One of the main difference between NodeJs and Typescript is:
- NodeJS can import modules dynamically
- Typescript module relied on static ES6 modules definition
The update will be a required step to Typescript, so do it! One important thing is you have to do all at once (or on standalone modules)
- use only
require()/module.exports🚫 - or only
import/export🚫
The purpose of this script is to make you FAST in this mission 🚀
npm i
node ./dist/main.js /path/to/your/project
# Follow the instructions, step by stepYour project has to be on Git. Use your file editor to see if the script worked as expected.
Two steps are mandatory to use import in Nodejs:
- All
"type":"module"to yourpackage.json - Run your node program with
node --es-module-specifier-resolution=node
Step 2 is required in order to not specify file extension in imports, which is more common to switch to Typscript.
By not writing extension, you will be able to switch a file ext from .js to .ts and not update every imports.
Add to you eslint config file
"parserOptions": {
"ecmaVersion": 2020,
"sourceType": "module"
},
|
🕸 CommonJS version // Global imports
const _ = require('lodash');
const sinon = require('sinon');
const { ObjectId } = require('mongodb');
const CustomNameRouter = require('express').Router;
// Local imports
const someFile = require(`../path/file`);
const myFunc = require(`../file2`).func;
const { myUtil } = require(`../file2`); |
✨ ES6 import version // Global imports
import _ from 'lodash';
import * as sinon from 'sinon';
import { ObjectId } from 'mongodb';
import { Router as CustomNameRouter } from 'express';
// Local imports
import * as someFile from "../path/file.js";
import { func as myFunc, myUtil } from "../file2.js"; |
|
🕸 CommonJS version const MYCONST = 89;
module.exports = { myFunc, MYCONST };
Object.assign(module.exports, { myFunc, MYCONST });
module.exports.someConst = {};
function myFunc(){} |
✨ ES6 import version export const MYCONST = 89;
export const someConst = {};
export function myFunc(){} |
It's usual with Nodejs to have index.js files export like this:
|
🕸 CommonJS version const myLib = require('./myLib');
const lib2 = require('./lib2/');
module.exports = { ...myLib, lib2, } |
✨ ES6 import version export * from './myLib.js';
export lib2 from './lib2/index.js'; |