Node error import assertString unexpected identifier/cannot use outside module

[sklawren]

Describe the bug
When compiling in node (with next.js, for example) or running Jest test, Validator always throws the following error whenever anything is imported.

For example, I have a React component that imports blacklist from validator (this happens with any import though).

import blacklist from 'validator/es/lib/blacklist';

Works fine in development, but when I run jest locally, I get the following error:

{import assertString from './util/assertString';
        ^^^^^^^^^^^^
SyntaxError: Unexpected identifier
at Runtime.createScriptFromCode (node_modules/jest-runtime/build/index.js:1258:14)
at Object.<anonymous> (src/utils/src/string.js:1:1)

OR in the CI for next.js (a different project, but same issue

/home/circleci/repo/node_modules/validator/es/lib/isURL.js:1
import assertString from './util/assertString';
^^^^^^
SyntaxError: Cannot use import statement outside a module

Additional context
Validator.js version: 13.5.2
Node.js version: 10.13.0 and 12.18.4
OS platform: MacOS

[fedeci]

Hi @sklawren, can you provide an example repo, please?

[sklawren]

It's super easy to replicate. It's 100% reproducible with a brand new CRA project.

1. Create a new Create React App npx create-react-app validator-test
2. Go into the project, and install validator npm i -S validator

Add a file called utils.js (or whatever):

import blacklist from 'validator/es/lib/blacklist';

export const sanitize = str => blacklist(str, 'a-z');

3. Modify the App.js file to import the sanitize function. You can copy paste this if you like.

import {sanitize} from './utils';
import './App.css';

function App() {
  const value = sanitize('a10c');
  return (
    <div className="App">
      {value}
    </div>
  );
}

export default App;

4. npm start - Works fine. You should see '10' in the browser.
5. npm test - Crashes.

 ({"Object.<anonymous>":function(module,exports,require,__dirname,__filename,global,jest){import assertString from './util/assertString';
                                                                                             ^^^^^^

    SyntaxError: Cannot use import statement outside a module

    > 1 | import blacklist from 'validator/es/lib/blacklist';
        | ^
      2 |
      3 | export const sanitize = str => blacklist(str, 'a-z');
      4 |

      at Runtime.createScriptFromCode (node_modules/jest-runtime/build/index.js:1350:14)
      at Object.<anonymous> (src/string.js:1:1)

[fedeci]

Try looking at facebook/create-react-app#9938 because this is a jest "problem" and not a validator.js one :)

[sklawren]

I tried that and it didn't work. What did work was changing it to:

import blacklist from 'validator/lib/blacklist';

I guess this doesn't tree-shake, but it works.

[p-iknow]

@sklawren
i have the same issue described above, and I solved using jest.config options, transform, and transformIgnorePattern option.
if you don't use typescript, you can use babel-jest instead of ts-jest

[tux-tn]

Looks like the issue is related to jest and not validator . Thank you @p-iknow for providing the answer.

[newsiberian]

I've faced w/ the same error while migrating my TS app to esm:

Node: 16.17.0

(node:85802) 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)

...

import assertString from './util/assertString';
^^^^^^

SyntaxError: Cannot use import statement outside a module
    at compileFunction (<anonymous>)
    at Object.compileFunction (node:vm:360:18)
    at wrapSafe (node:internal/modules/cjs/loader:1055:15)
    at Module._compile (node:internal/modules/cjs/loader:1090:27)
    at Object.Module._extensions..js (node:internal/modules/cjs/loader:1180:10)
    at Module.load (node:internal/modules/cjs/loader:1004:32)
    at Function.Module._load (node:internal/modules/cjs/loader:839:12)
    at ModuleWrap.<anonymous> (node:internal/modules/esm/translators:170:29)
    at ModuleJob.run (node:internal/modules/esm/module_job:193:25)
    at async Promise.all (index 0)

[JaneJeon]

I see this with vanilla ESM + TypeScript as well, as noted in #1759