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I want to use import fs from 'fs' in JavaScript. Here is a sample:

import fs from 'fs'

var output = fs.readFileSync('someData.txt')

console.log(output)

The error I get when I run my file using node main.js is:

(function (exports, require, module, __filename, __dirname) { import fs from 'fs
'
                                                              ^^^^^^
SyntaxError: Unexpected token import

What should I install in Node.js in order to achieve importing modules and functions from other places?

I want to use import fs from 'fs' in JavaScript. Here is a sample:

import fs from 'fs'

var output = fs.readFileSync('someData.txt')

console.log(output)

The error I get when I run my file using node main.js is:

(function (exports, require, module, __filename, __dirname) { import fs from 'fs
'
                                                              ^^^^^^
SyntaxError: Unexpected token import

What should I install in Node.js in order to achieve importing modules and functions from other places?

• javascript
• es6-modules

Share Improve this question Follow edited Oct 3, 2020 at 19:23 Peter Mortensen 31.6k2222 gold badges109109 silver badges133133 bronze badges asked Apr 25, 2017 at 23:01 escplat12escplat12 2,49144 gold badges2525 silver badges3535 bronze badges 3

• 1 A transpiler. Or the next node release from the future. – Bergi Commented Apr 25, 2017 at 23:04
• Look at my answer to get it working! – nomis Commented Sep 4, 2018 at 22:37
• 1 While Node 14 allows (for example) import fs from 'fs/promises' syntax, on earlier versions, you'll have to create an alias using import { promises as fs } from syntax – imrok Commented Jan 27, 2021 at 9:07

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11 Answers 11

Sorted by: Reset to default 219

For default exports you should use:

import * as fs from 'fs';

Or in case the module has named exports:

import {fs} from 'fs';

Example:

//module1.js

export function function1() {
  console.log('f1')
}

export function function2() {
  console.log('f2')
}

export default function1;

And then:

import defaultExport, { function1, function2 } from './module1'

defaultExport();  // This calls function1
function1();
function2();

Additionally, you should use Webpack or something similar to be able to use ES6 import

ES6 modules support in Node.js is fairly recent; even in the bleeding-edge versions, it is still experimental. With Node.js 10, you can start Node.js with the --experimental-modules flag, and it will likely work.

To import on older Node.js versions - or standard Node.js 10 - use CommonJS syntax:

const fs = require('fs');

Building on RobertoNovelo's answer:

import * as fs from 'fs';

is currently the simplest way to do it.

It was tested with a Node.js project (Node.js v10.15.3), with esm, allowing to use import.

In order to use import { readFileSync } from 'fs', you have to:

1. Be using Node.js 10 or later
2. Use the --experimental-modules flag (in Node.js 10), e.g. node --experimental-modules server.mjs (see #3 for explanation of .mjs)
3. Rename the file extension of your file with the import statements, to .mjs, .js will not work, e.g. server.mjs

The other answers hit on 1 and 2, but 3 is also necessary. Also, note that this feature is considered extremely experimental at this point (1/10 stability) and not recommended for production, but I will still probably use it.

Here's the Node.js 10 ESM documentation.

Go to package.json file and add:

"type": "module"

This worked for me!

It is 2023, In the current version node 16+:

import {readFileSync} from "fs"

const string_output = readFileSync("path-to-file", 'utf8')
// the rest

If you do not give the second argument, encoding 'utf8', it will return a binary file

If we are using TypeScript, we can update the type definition file by running the command npm install @types/node from the terminal or command prompt.

If you want your statement import fs from 'fs' to be executable, you can make your file extension .mjs instead of .js. i.e filename.mjs

The new ECMAScript module support is able natively in Node.js 12

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