'import' and 'export' may only appear at the top level

[maneetgoyal]

• Rollup Plugin Name:
• Rollup Plugin Version: @rollup/plugin-commonjs
• Rollup Version: 11.1.0
• Operating System (or Browser): Mac OS
• Node Version: 12.13.1

How Do We Reproduce?

• This issue was raised earlier too: 'import' and 'export' may only appear at the top level rollup-plugin-commonjs#90
• Some change via Dynamic require #206 or feat(commonjs): export properties defined using Object.defineProperty(exports, ..) #222 might be causing this issue

Expected Behavior

Bundling worked with lodash-es without any issues till v. 11.0.2.

Actual Behavior

!] Error: 'import' and 'export' may only appear at the top level
abc: ../../node_modules/lodash-es/isBuffer.js (1:0)
abc: 1: import root from './_root.js';
abc:    ^
abc: 2: import stubFalse from './stubFalse.js';
abc: Error: 'import' and 'export' may only appear at the top level
abc:     at error (/xxx/node_modules/rollup/dist/shared/rollup.js:10399:30)
abc:     at Module.error (/xxx/node_modules/rollup/dist/shared/rollup.js:14789:16)
abc:     at tryParse (/xxx/node_modules/rollup/dist/shared/rollup.js:14682:23)
abc:     at Module.setSource (/xxx/node_modules/rollup/dist/shared/rollup.js:15080:30)
abc:     at /xxx/node_modules/rollup/dist/shared/rollup.js:17086:20
abc:     at runNextTicks (internal/process/task_queues.js:58:5)
abc:     at processImmediate (internal/timers.js:412:9)
abc:     at async Promise.all (index 114)
abc:     at async Promise.all (index 5)
abc:     at async Promise.all (index 0)
abc: error Command failed with exit code 1.

[shellscape]

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3. Using the REPL at https://rollupjs.org/repl/

Please add a reproduction and we'll be happy to triage further.

Please refrain from +1 replies. They'll be removed.

[CadenP]

Here's a reproduction with the specific package (not a direct dependency) that's causing me issues:
https://repl.it/repls/PoliticalTestyMegahertz

Note that @rollup/[email protected] works, but @rollup/[email protected] fails.

[shellscape]

Thanks for adding that repro.

[Conduitry]

There's another helpful-sounding comment here that tries to dig a little more into what's happening.

[shellscape]

@tiefenb Please don't add +1 comments to issues in this repo. If you have a reproduction to add, please do share it but use one of the methods mentioned above.

[eswat2]

Rollup Plugin Name: @rollup/plugin-commonjs
Rollup Plugin Version: 11.1.0
Rollup Version: 2.6.1
Operating System: Mac OS (10.15.4)
Browser: Chrome (83.0.4103.7)
Node Version: 12.16.1

i have a small Svelte demo that i keep up to date with the latest toolchains and i found that it fails to build when i updated @rollup/plugin-commonjs from "11.0.2" to "11.1.0" this weekend.

works -- https://github.com/eswat2/s4e-autos
broken -- https://github.com/eswat2/s4e-autos/tree/broken-build-compile-error-import-export

The only difference between these 2 is the version of @rollup/plugin-commonjs in package.json.

Running yarn build in master for this repo, you see what you'd expect:

➜  s4e-autos git:(master) yarn build
yarn run v1.22.4
warning ../package.json: No license field
$ rollup -c

src/main.js → public/build/bundle.js...
created public/build/bundle.js in 10.6s
✨  Done in 11.15s.

Now, running yarn build in the branch gives this:

➜  s4e-autos git:(broken-build-compile-error-import-export) yarn build
yarn run v1.22.4
warning ../package.json: No license field
$ rollup -c

src/main.js → public/build/bundle.js...
[!] Error: 'import' and 'export' may only appear at the top level
node_modules/symbol-observable/es/index.js (2:0)
1: /* global window */
2: import ponyfill from './ponyfill.js';
   ^
3:
4: var root;
Error: 'import' and 'export' may only appear at the top level
    at error (/Users/richardhess/github/zeit/s4e-autos/node_modules/rollup/dist/shared/rollup.js:10399:30)
    at Module.error (/Users/richardhess/github/zeit/s4e-autos/node_modules/rollup/dist/shared/rollup.js:14789:16)
    at tryParse (/Users/richardhess/github/zeit/s4e-autos/node_modules/rollup/dist/shared/rollup.js:14682:23)
    at Module.setSource (/Users/richardhess/github/zeit/s4e-autos/node_modules/rollup/dist/shared/rollup.js:15080:30)
    at /Users/richardhess/github/zeit/s4e-autos/node_modules/rollup/dist/shared/rollup.js:17086:20
    at async Promise.all (index 3)
    at async Promise.all (index 1)
    at async Promise.all (index 1)
    at async Promise.all (index 1)
    at async Promise.all (index 0)

error Command failed with exit code 1.
info Visit https://yarnpkg.com/en/docs/cli/run for documentation about this command.

I hope this example helps you resolve the issue...

Richard

UPDATE: 2020.04.14

i refactored master to use svql instead of svelte-apollo and after i got it all working i upgraded to @rollup/plugin-commonjs 11.1.0 and it all works like a charm. The branch is still broken if i try to upgrade, but master is working fine with all the latest npm packages.

Not sure if this helps or hurts your attempt to solve the problem, but it's another insight into the problem...

[eswat2]

seems like ponyfill.js is one of the common elements in a few of the issues reported/linked here:

node_modules/symbol-observable/es/index.js

import ponyfill from './ponyfill.js';

Looking at the code behind that you find this:

export default function symbolObservablePonyfill(root) {
	var result;
	var Symbol = root.Symbol;

	if (typeof Symbol === 'function') {
		if (Symbol.observable) {
			result = Symbol.observable;
		} else {
			result = Symbol('observable');
			Symbol.observable = result;
		}
	} else {
		result = '@@observable';
	}

	return result;
};

and that was last updated 4 years ago specifically to support rollup:

benlesh/symbol-observable@7a41de9

https://github.com/benlesh/symbol-observable/blob/master/es/ponyfill.js

Maybe it's time for a rewrite?...

[LarsDenBakker]

I ran into this issue as well, I did some debugging and I found that this file is incorrectly detected as a commonjs module: https://unpkg.com/[email protected]/es/index.js?module

It's possible this is because it checks for a module global. commonjs plugin 11.1.0 brings dynamic imports support, which changed quite a lot of things in the plugin.

[spectras]

I hit the same issue. For me it's React that is not detected correctly. Which is interesting because React's index.js is like this:

'use strict';

if (process.env.NODE_ENV === 'production') {
  module.exports = require('./cjs/react.production.min.js');
} else {
  module.exports = require('./cjs/react.development.js');
}

Unfortunately I could not dig further at the moment, but it looks like when upgrading from 11.0.2 to 11.1.0, this now gets interpreted as imports within a if. Triggering the same error message as OP's.

[arantes555]

For me the error log is a bit different:

SyntaxError: /Users/XXXX/node_modules/@sentry/utils/esm/misc.js: 'import' and 'export' may only appear at the top level (4:0)

  2 | 
  3 | var misc = commonjsHelpers.createCommonjsModule(function (module) {
> 4 | import { isString } from './is';
    | ^
  5 | import { snipLine } from './string';
  6 | /**
  7 |  * Requires a module which is protected against bundler minification.
    at Parser.raise (/Users/XXXX/node_modules/@babel/parser/lib/index.js:6325:17)

But when I do a head ./node_modules/@sentry/utils/esm/misc.js, it starts with:

import { isString } from './is';
import { snipLine } from './string';

Without the commonjsHelpers.createCommonjsModule thing.

So it looks like the file already passed through the commonJS plugin somehow, and is passing again ?

[shellscape]

Notice to Future Commenters

Please do not reply with "me too" or "same here" or "+1" replies unless you are providing specifics on the code in the commonjs plugin that can be used for triage. We have enough of a sample of what isn't working at this point.

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[FredKSchott]

Like others I encountered this error through node_modules/symbol-observable/es/index.js. If it helps to find out what's wrong, I noticed that changing that file name index.js -> index.mjs seemed to solve the problem for that specific file.

[tommedema]

This was resolved for me by downgrading @rollup/plugin-commonjs from 11.1.0 to 11.0.2, though this did introduce a warning that it's expecting a peer dependency of rollup@^1.20.0

[shellscape]

@lukastaegert can you provide any guidance on this one?

[mikeifomin]

Temporary fixed with exclude option (https://github.com/rollup/plugins/tree/master/packages/commonjs#exclude)
in rollup.config.js

   commonjs({
       exclude: ['node_modules/symbol-observable/es/*.js'],
    }),

[manucorporat]

Wondering if this is causing by the removal of this early exit:

cbc341d?diff=split#r38821925

[ivan-nemtinov]

The simplest solution for now: import correct index file directly instead of letting rollup to determine module type:
import $$observable from 'symbol-observable/index'

[FredKSchott]

This isn't an import that I've written myself / that I can control, it's one inside of my node_modules directory.

Just in case my original comment downplayed the severity, this is a fairly serious bug. Snowpack is stuck on "~11.0.0" until this is resolved.

[danielgindi]

It seems like detection of whether to transform the module or not should be a bit more complicated.
What happens is that it detects usage of module due to the } else if (typeof module !== 'undefined') { which is meant for detecting node vs browser envs.
But it's only sniffing around, not using any require call from module.
I'm working on a fix to take this into account.

[danielgindi]

There's a fix pending, with the test replicating the repl supplied by @CadenP.

In the future, please try to keep repros localized, without external dependencies. This helps in detection of the pain point.

[CadenP]

There's a fix pending

Great news! Thanks for all of your work!

In the future, please try to keep repros localized, without external dependencies. This helps in detection of the pain point.

Makes sense, I'll try to do that.

[tobius]

What version will this be available in?

[shellscape]