Typescript: Cannot use import statement outside a module

62
votes

I have a .ts file in node js (latest version of node.js for 07.10.19) app with importing node-module without default export. I use this construction: import { Class } from 'abc'; When i run the code, i have this error: Cannot use import statement outside a module.

In the network i see many solutions for this problem (for .js), but it not helps to me, maybe because i have typescript file. Here's my code:

import { Class } from 'abc';
module.exports = { ...
    execute(a : Class ,args : Array<string>){ ...

Here's my tsconfig.json:

{
  "compilerOptions": {
    "target": "es6",
    "module": "commonjs",

    "strict": true
  }
}
5
typescriptecmascript-6
Are you running this in a browser? Is the import statement the first line in your file? – Evert
Can you please post your tsconfig.json file? When you compile in Typescript, you can determine which type of modules it produces, and the valid types may differ depending on which environment (browser/NodeJS) and which other modules (require vs import) you use. Just to give you a sense of how complicated this is, Node has some documentation about import vs require and how to make them work together. – Jeff Bowman
If you are using module.exports syntax, you're probably not in an ES6 module. – Bergi
Evert, this is node js app, tsconfig will be add soon – Zerumi
Ok, i can't use require because Cannot find namespace 'abc' when using construction execute(a : abc.Class... – Zerumi

5 Answers

29
votes

Adding "type": "module" to package.json will tell Node you are using ES2015 modules, which should get rid of the error, but then you will need to tell Typescript to generate this type of module by setting "module": "es2015" instead of "commonjs" in tsconfig.json.

This however causes a problem with the current code because although you are using an ES6 import {} statement you are exporting using the commonJS module.exports = {} syntax, and Node’s ES module loader will have an issue with it. There are two ways to deal with it:

  1. Keep the module.exports but tell Node to interpret this file as commonJS by giving it a .cjs extension.
  2. Change the export statement to ES2015 syntax: export function execute(…)..

The first option could get a bit tricky because the compiler will output .js files and you’d have to change it to .cjs all the time (as far as I know). With the second option you should be able to run the file with Node (including the --experimental-modules flag for versions < 13.8).

If you absolutely need to use commonJS, perhaps it is better to install the type definitions for Node: @types/node and change the import to commonJS format: require('abc') and keep the rest of the settings as they are (though you can add “type”: “commonjs” to package.json to be explicit).

5
votes

I had very similar issue. I had to install nodemon and always start script through nodemon index.ts

yarn add -D nodemon

package.json

"scripts": {
   "start": "nodemon index.ts"
}

or to specify the file from the command line

package.json

"scripts": {
   "nodemon": "nodemon $1"
}
2
votes

Make sure your "main" field in package.json is pointing to the compiled index.js and not the index.ts

0
votes

There can be a lot of of possibilities for getting,

SyntaxError: Cannot use import statement outside a module

while running typescript.

In my setup, I was importing a module called, AbModule (AbModule has class AbClassName) from my script testab.ts.

testab.ts had import stmt,

import {AbClassName} = 'testAdapterDir/AbModule.po.ts';

However, AbModule had all *.ts files and there were *.js files were not present. fix is,

You may get errors in running the below code but you can safely ignore them.

cd AbModule path
tsc *.ts

Now AbModule should contain compiled files all *.js too. Now run testab.ts and noticed that the mentioned error does not exist anymore,

-3
votes

install package ts-node and change your package.json

"scripts": {
    "dev": "ts-node index.ts"
  }

UPD: This can occur while using ts-node