CODEWITHSUNDEEP
javascriptnode.jsimportexport
Serket
Serket

Reputation: 4485

Node.js: SyntaxError: Cannot use import statement outside a module

I am getting this error SyntaxError: Cannot use import statement outside a module when trying to import from another javascript file. This is the first time I'm trying something like this. The main file is main.js and the module file is mod.js.

main.js:

import * as myModule from "mod";
myModule.func();

mod.js:

export function func(){
    console.log("Hello World");
}

How can I fix this? Thanks

Upvotes: 159

Views: 328129

Answers (11)

Prince
Prince

Reputation: 163

In my case, I had my typescript project and I wanted to run a ts file, while running node file.ts Turns out I was using the wrong command to run the file.

Command to use: npx tsc file.ts

Followed by: node file.js

Running the first command will compile the ts and generate a new file with same name but ts extension.

Upvotes: 0

Nate Ferrero
Nate Ferrero

Reputation: 1458

I was running into this issue with Node 18 with a single file src/index.js that uses import statements, here's the error message I got:

(node:13859) Warning: To load an ES module, set "type": "module" in the package.json or use the .mjs extension.
(Use `node-18 --trace-warnings ...` to show where the warning was created)
[...redacted...]src/index.js:5
import { createServer } from 'node:http'
^^^^^^

SyntaxError: Cannot use import statement outside a module
    at internalCompileFunction (node:internal/vm:73:18)
    at wrapSafe (node:internal/modules/cjs/loader:1178:20)
    at Module._compile (node:internal/modules/cjs/loader:1220:27)
    at Module._extensions..js (node:internal/modules/cjs/loader:1310:10)
    at Module.load (node:internal/modules/cjs/loader:1119:32)
    at Module._load (node:internal/modules/cjs/loader:960:12)
    at Function.executeUserEntryPoint [as runMain] (node:internal/modules/run_main:86:12)
    at node:internal/main/run_main_module:23:47

The only things I had to do to resolve this was rename my src/index.js to src/index.mjs and start it with the command node src/index.mjs (node src finds index.js but not index.mjs). Happy day:

$ node src/index.mjs 
Server is running on http://localhost:8080

Upvotes: 4

Sibevin Wang
Sibevin Wang

Reputation: 4558

You can run a js script by node --experimental-modules without changing package.json as below:

node --experimental-modules ./path/to/your/js/script.mjs

Note that you need change your script ext to .mjs, otherwise a SyntaxError: Cannot use import statement outside a module error will occur.

Upvotes: 1

kob003
kob003

Reputation: 3737

For browser(front end): add type = "module" inside your script tag i.e

<script src="main.js" type="module"></script>

For nodejs: add "type": "module", in your package.json file

{
  "name": "",
  "version": "",
  "description": "",
  "main": "",
  "type": "module",
   ....
}

Upvotes: 15

Achraf Ghellach
Achraf Ghellach

Reputation: 2194

In order to use the import syntax (ESModules), you need to add the following to your package.json at the top level:

{
    // ...
    "type": "module",
}

If you are using a version of Node earlier than 13, you additionally need to use the --experimental-modules flag when you run the program:

node --experimental-modules program.js

Upvotes: 203

Snowcat
Snowcat

Reputation: 526

I got the same issue but in another module (python-shell). I replaced the code as follows:

import {PythonShell} from 'python-shell'; (original code)
let {PythonShell} = require('python-shell')

That solved the issue.

Upvotes: 2

Simone
Simone

Reputation: 1337

If you are in the browser (instead of a Node environment), make sure you specify the type="module" attribute in your script tag. If you want to use Babel, then it must be type="text/babel" data-plugins="transform-es2015-modules-umd" data-type="module".

Upvotes: 1

johnnyBoy
johnnyBoy

Reputation: 125

I had this issue trying to run mocha tests with typescript. This isn't directly related to the answer but may help some.

This article is quite interesting. He's using a trick involving cross-env, that allows him to run tests as commonjs module type. That worked for me.

// package.json
{
  ...
  "scripts": {
    "test": "cross-env TS_NODE_COMPILER_OPTIONS='{ \"module\": \"commonjs\" }' mocha -r ts-node/register -r src/**/*.spec.ts"
  }
}

Upvotes: 1

ro_alli
ro_alli

Reputation: 49

I recently encountered this problem. This solution is similar to the top rated answer but with some ways I found worked for me.

In the same directory as your modules create a package.json file and add "type":"module". Then use import {func} from "./myscript.js";. The import style works when run using node.

Upvotes: 4

Lekia
Lekia

Reputation: 184

In addition to the answers above, note by default(if the "type" is omitted) the "type" is "commonjs". So, you have explicitly specify the type when it's "module". You cannot use an import statement outside a module.

Upvotes: 1

gautam1168
gautam1168

Reputation: 701

Use commonjs syntax instead of es module syntax:

module.exports.func = function (){
    console.log("Hello World");
}

and

const myMod = require("./mod")
myMod.func()

Otherwise, if you want to use es modules you have to do as the answer by Achraf Ghellach suggests

Upvotes: 35

Related Questions