Syntax error the requested module dell does not provide an export named default

The reason it didn’t work is that Vue provides a named export, whereas you are trying to import it as though it had a default export.

To make a named import (which you must do with named exports), you need to wrap the name of the export you want to import in curly braces, so {} around Vue like this:

import { Vue } from 'vue';
      // ^^^ name of export

It will work

The thing you want to do is import vue but it doesnot have a default export function or either the default thing to export is not set in vue module. So you have to select function named vue by adding curly braces.

If it had a default export function, then your code would have worked and in that case you could write anything in place of vue like below:

import anyname from 'vue'

anyname is name whatever you want.

StheSthe

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import { foo } from '../lib/index.js';
         ^^^
SyntaxError: The requested module '../lib/index.js' does not provide an export named 'foo'

format be assigned as commonjs

and loaderInstance is the commonjs loader

ESMLoader directly use v8 esm import, I think we currently haven’t checker if a source is esm or cjs

There seems to be a bug here in the loader itself. This module should not be loaded as ESM, but rather as CJS. Was able to make the repro even smaller

index.mjs

import { foo } from './index.cjs';
console.log(foo());

index.cjs

export function foo() {
    return 'foo';
}

Even though this has ESM syntax in it it should fail to even import as you are attempting to do a named exports of the CJS module. pinging @jkrems and @guybedford to take a look

I don’t think it’s a bug, because you not mark the file as the esm module. and it’s just an incorrect error message. and can we add support that esm loader can check the js file as mjs file and log the message like Load js as commonjs error

Even though this has ESM syntax in it it should fail to even import as you are attempting to do a named exports of the CJS module.

Maybe I’m missing something but this looks to error correctly because of the lack of an export named foo, at least according to the issue description:

SyntaxError: The requested module '../lib/index.js' does not provide an export named 'foo'

Even though this has ESM syntax in it it should fail to even import as you are attempting to do a named exports of the CJS module.

Maybe I’m missing something but this looks to error correctly because of the lack of an export named foo, at least according to the issue description:

SyntaxError: The requested module '../lib/index.js' does not provide an export named 'foo'

why correctly?

when

import { foo } from '../lib/index.js';

import {foo} from '../lib/index.js';
        ^^^
SyntaxError: The requested module '../lib/index.js' does not provide an export named 'foo'

but, when

import foo from '../lib/index.js';
``

```bash
export function foo() {
^^^^^^

SyntaxError: Unexpected token 'export'

this is two kinds of different error types, and the first error message will misleading users.

another example

// change https://github.com/dandv/lib-does-not-provide-export-foo/blob/master/lib/index.js
exports.foo = 123

the error message still occur

import { foo } from '../lib/index.js';
         ^^^
SyntaxError: The requested module '../lib/index.js' does not provide an export named 'foo'

but I change use-lib/index.js to

import md from '../lib/index.js';
console.log(md);

thing go weird

(node:24052) ExperimentalWarning: The ESM module loader is experimental.
{ foo: 123 }

I’m not saying it’s not confusing right now. The issue is just: This happens before we even try to run the code and that’s when a CommonJS syntax errors would happen. It may be possible to somehow detect this specific error and try to gather some more context but it would be tricky.

To go into what you were seeing in your last comment: Exports in ES modules are very different from the «exports» object in CommonJS, confusingly. Each module export is a variable/identifier. The following CommonJS code doesn’t create a new variable, it only sets a property on one:

So afterwards the CommonJS still only has a single export — the module.exports object. That’s all a CommonJS file exports, from an ES module perspective. Your later code could be rewritten as:

import { default as md } from '../lib/index.js';
console.log(md);

So your importing the default export (the module.exports object) from ../lib/index.js which is an object that has a property foo, as set above.

I’m not saying it’s not confusing right now. The issue is just: This happens before we even try to run the code and that’s when a CommonJS syntax errors would happen. It may be possible to somehow detect this specific error and try to gather some more context but it would be tricky.

To go into what you were seeing in your last comment: Exports in ES modules are very different from the «exports» object in CommonJS, confusingly. Each module export is a variable/identifier. The following CommonJS code doesn’t create a new variable, it only sets a property on one:

So afterwards the CommonJS still only has a single export — the module.exports object. That’s all a CommonJS file exports, from an ES module perspective. Your later code could be rewritten as:

import { default as md } from '../lib/index.js';
console.log(md);

So your importing the default export (the module.exports object) from ../lib/index.js which is an object that has a property foo, as set above.

Yeah, I get you

Marking as a documentation issue since this is a common error that should be well documented. //cc @GeoffreyBooth

I think this needs more than just documentation. If you directly run node lib/index.js, you’ll see a really nice little warning:

$ node index.js
(node:83643) Warning: To load an ES module, set "type": "module" in the package.json or use the .mjs extension.
(Use `node --trace-warnings ...` to show where the warning was created)
/private/tmp/tp/lib-does-not-provide-export-foo/lib/index.js:1
export function foo() {
^^^^^^

SyntaxError: Unexpected token 'export'

I would have wanted this case to show a better SyntaxError, and maybe a warning, something like:

(node:83643) Warning: '../lib/index.js' is a CommonJS module,
but ES modules can't import named exports from CommonJS modules
SyntaxError: The requested module '../lib/index.js' does not provide an export named 'foo'

I’ll note that the error is marginally better if you try to import the default export without braces, like this:

import foo from '../lib/index.js'

export function foo() {
^^^^^^

SyntaxError: Unexpected token 'export'

I just realized that the scope of this is bigger than «ESM misinterpreted as CJS.» This error applies even when the imported script is legit CJS with named exports.

dependency.cjs

module.exports.name = "foo";

dependent.mjs

import {name} from './dependency.cjs';
console.log({name});

You get this: SyntaxError: The requested module './dependency.cjs' does not provide an export named 'name' which is only «true» because ES modules aren’t allowed to import CJS named exports.

The SyntaxError in this case should be much clearer:

SyntaxError: The requested module './dependency.cjs' is a CommonJS module, which can only provide a default export, not named exports, to an ES module script.

I just realized that the scope of this is bigger than «ESM misinterpreted as CJS.» This error applies even when the imported script is legit CJS with named exports.

dependency.cjs

module.exports.name = "foo";

dependent.mjs

import {name} from './dependency.cjs';
console.log({name});

You get this: SyntaxError: The requested module './dependency.cjs' does not provide an export named 'name' which is only «true» because ES modules aren’t allowed to import CJS named exports.

The SyntaxError in this case should be much clearer:

SyntaxError: The requested module './dependency.cjs' is a CommonJS module, which can only provide a default export, not named exports, to an ES module script.

How do you re-write this so it works?

This error was considerably enhanced in Node 14.8 I believe. Now the error message says:

SyntaxError: The requested module './dependency.cjs' is expected to be of type
CommonJS, which does not support named exports. CommonJS modules can be
imported by importing the default export.
For example:
import pkg from './dependency.cjs';
const {name} = pkg;

And, indeed, that’s what you’d do to fix dependent.mjs.

import pkg from './dependency.cjs';
const {name} = pkg;
console.log({name});

@dandv @dfabulich @kathy-ems Node.js 14.13.0 added support for named CJS exports, see #35249 and this change has also been backported to Node.js v12.20.0.

Can you confirm that

import { foo } from '../lib/index.js';

now also works for you if index.js is a CJS file?

How Do I Solve This I’m New to Node JS?

How Do I Solve This I’m New to Node JS?

Use the suggested code from the error message.

Closing as I think this has been addressed.

What do we do when it’s a dependency that’s doing the import‘ing?

I’m receiving this error and don’t have control over the dependency’s code. Any suggestions?

Have you tried reporting this as a bug to the dependency which is causing the issue?

What do we do when it’s a dependency that’s doing the import‘ing?

I’m receiving this error and don’t have control over the dependency’s code. Any suggestions?

Yeah you have to provide a fix in the repo. I’m facing this currently and it’s a bit frustrating.