Node.js : CommonJS to ES Module in 4 Steps without Transpiling or Babel Node
With some adjustment we don’t need babel and transpiling.
Just Node.js. Up and running !
First of all, add type: module into your package.json
Here we go to fix the error.
Problem 1: File Naming
The module need to be the exact name.
It also makes sense to set this. Some reason behind this is that the module might guess wrong when you have .js and .ts in the same directory.
directory
|_ a.js
|_ b.jsimport a from 'a'
// NOT WOKRING
import a from 'a.js'
// WOKRING
|_ a.js
|_ b.jsimport a from 'a'
// NOT WOKRING
import a from 'a.js'
// WOKRING
Problem 2: __dirname
After migration, the __dirname is not working anymore.
Here are the alternative:
// BEFORE
readFileSync(path.join(__dirname, './data.proto'))// AFTER
readFileSync(new URL('./data.proto', import.meta.url))
readFileSync(path.join(__dirname, './data.proto'))// AFTER
readFileSync(new URL('./data.proto', import.meta.url))
Problem 3: Incompatible CJS Named import
Sometimes, there are lib that’s not yet compatible with ‘Named import’
import sequelize from 'sequelize'
const { STRING, ARRAY } from sequelize
const { STRING, ARRAY } from sequelize
Problem 4: ReferenceError: require is not defined
Sometimes, there are the mixin style required
For example, winston-daily-rotate-file this one mutate the imported winston instance.
import { createRequire } from 'module';
const require = createRequire(import.meta.url);require('...')
// working !
const require = createRequire(import.meta.url);require('...')
// working !
Here we go. Now we finish migrating.
Cheers !
