I wrote a simple plugin:
export default function() {
return {
visitor: {
Program: {
enter() {
console.log('Program Entered!');
},
exit() {
console.log('Program Exited!');
},
},
},
};
}
when I run webpack - it compiles my project successfully
but when I run jest test - it fails with error:
Starting script: test
FAIL unit-tests src/common/App.test.js
● Test suite failed to run
Jest encountered an unexpected token
This usually means that you are trying to import a file which Jest cannot parse, e.g. it's not plain JavaScript.
By default, if Jest sees a Babel config, it will use that to transform your files, ignoring "node_modules".
Here's what you can do:
• To have some of your "node_modules" files transformed, you can specify a custom "transformIgnorePatterns" in your config.
• If you need a custom transformation specify a "transform" option in your config.
• If you simply want to mock your non-JS modules (e.g. binary assets) you can stub them out with the "moduleNameMapper" config option.
You'll find more details and examples of these config options in the docs:
https://jestjs.io/docs/en/configuration.html
Details:
/../project/config/babel/myplugin.js:1
(function (exports, require, module, __filename, __dirname) { export default function() {
^^^^^^
SyntaxError: Unexpected token export
if I remove my plugin from babel configuration - tests pass
why it complaints on my plugin? it is located outside jests rootDir - src.
what is wrong?
Related
I have a Vue.js application where two files contain:
import axios from "axios"
These files are located in src/lib within the application and include the import statement on their first line.
Running tests on Github causes Axios 1.0.0 to be installed, no matter what the package.json says, and now any test involving these files fails with the above error.
Changing the statement to const axios = require("axios") fails also; node_modules/axios/index.js contains an import statement on line 1 and the exception is thrown there.
A suggestion I've seen quite often for such issues is to add "type": "module" to package.json (which is at the same level as src/). This causes all tests to fail with a demand to rename vue.config.js as vue.config.cjs. Doing that gets me: Error: You appear to be using a native ECMAScript module configuration file, which is only supported when running Babel asynchronously, which I do not understand.
Can anyone suggest what to do here?
I was able to fix this error by forcing jest to import the commonjs axios build by adding
"jest": {
"moduleNameMapper": {
"axios": "axios/dist/node/axios.cjs"
}
},
to my package.json. Other solutions using transformIgnorePatterns didn't work for me.
The 1.x.x version of axios changed the module type from CommonJS to ECMAScript.
The 0.x.x version of axios index.js file
module.exports = require('./lib/axios');
The 1.x.x version of axiox index.js file
import axios from './lib/axios.js';
export default axios;
Basically, jest runs on Node.js environment, so it uses modules following the CommonJS.
If you want to use axios up to 1.x.x, you have to transpile the JavaScript module from ECMAScript type to CommonJS type.
Jest ignores /node_modules/ directory to transform basically.
https://jestjs.io/docs/27.x/configuration#transformignorepatterns-arraystring
So you have to override transformIgnorePatterns option.
There are two ways to override transformIgnorePatterns option.
jest.config.js
If your vue project uses jest.config.js file, you add this option.
module.exports = {
preset: "#vue/cli-plugin-unit-jest",
transformIgnorePatterns: ["node_modules/(?!axios)"],
...other options
};
package.json
If your vue project uses package.json file for jest, you add this option.
{
...other options
"jest": {
"preset": "#vue/cli-plugin-unit-jest",
"transformIgnorePatterns": ["node_modules\/(?!axios)"]
}
}
This regex can help you to transform axios module and ignore others under node_modules directory.
https://regexper.com/#node_modules%5C%2F%28%3F!axios%29
Updating the version of jest to v29 fixed this in my project. It could be the case that you have an incompatible jest version.
I had the same issues and was able to solve this by using jest-mock-axios library
I experience similar problem but the error is caused by jest.
All the tests trying to import axios fail and throw the same exception:
Test suite failed to run
Jest encountered an unexpected token
This usually means that you are trying to import a file which Jest cannot parse, e.g. it's not plain JavaScript.
By default, if Jest sees a Babel config, it will use that to transform your files, ignoring "node_modules".
Here's what you can do:
• If you are trying to use ECMAScript Modules, see https://jestjs.io/docs/en/ecmascript-modules for how to enable it.
• To have some of your "node_modules" files transformed, you can specify a custom "transformIgnorePatterns" in your config.
• If you need a custom transformation specify a "transform" option in your config.
• If you simply want to mock your non-JS modules (e.g. binary assets) you can stub them out with the "moduleNameMapper" config option.
You'll find more details and examples of these config options in the docs:
https://jestjs.io/docs/en/configuration.html
Details:
/monorepo/node_modules/axios/index.js:1
({"Object.<anonymous>":function(module,exports,require,__dirname,__filename,global,jest){import axios from './lib/axios.js';
^^^^^^
SyntaxError: Cannot use import statement outside a module
1 | import { describe, expect, it } from '#jest/globals'
> 2 | import axios from 'axios'
The solution is simply tell jest that axios should be transformed with babel:
const esModules = ['lodash-es', 'axios'].join('|')
# add these entries in module.exports
transform: {
[`^(${esModules}).+\\.js$`]: 'babel-jest',
},
transformIgnorePatterns: [`node_modules/(?!(${esModules}))`],
Note: I'm using Quasar Vue and this is their implementation.
Quick fix
Update the npm run test script from
"test": "react-scripts test",
to
"test": "react-scripts test --transformIgnorePatterns \"node_modules/(?!axios)/\"",
In my case I had to add the following line to the moduleNameMapper object in the jest config:
axios: '<rootDir>/node_modules/axios/dist/node/axios.cjs',
I had the same issue, it works fine when changing axios to fetch.
axios (Fail)
try {
const response = await axios("api/fruit/all");
return response.data;
} catch (error) {
return error;
}
Fetch (Works fine)
try {
const response = await fetch("api/fruit/all",{method:"GET"});
const data = await response.json();
return data;
} catch (error) {
return error;
}
i write a chess game by konva.js and typescript.
now i want to test it with ts-jest, but error happen when import Konva.
here is error messenge.
i know it possibly cause by esModule compiler.
i have tried to add konva in transformIgnorePatterns ,but not work.
or i should mock konva by _mock_?
how i fix it ,thanks all.
Jest encountered an unexpected token
Jest failed to parse a file. This happens e.g. when your code or its dependencies use non-standard JavaScript syntax, or when Jest is not configured to support such syntax.
Out of the box Jest supports Babel, which will be used to transform your files into valid JS based on your Babel configuration.
By default "node_modules" folder is ignored by transformers.
Here's what you can do:
• If you are trying to use ECMAScript Modules, see https://jestjs.io/docs/ecmascript-modules for how to enable it.
• If you are trying to use TypeScript, see https://jestjs.io/docs/getting-started#using-typescript
• To have some of your "node_modules" files transformed, you can specify a custom "transformIgnorePatterns" in your config.
• If you need a custom transformation specify a "transform" option in your config.
• If you simply want to mock your non-JS modules (e.g. binary assets) you can stub them out with the "moduleNameMapper" config option.
You'll find more details and examples of these config options in the docs:
https://jestjs.io/docs/configuration
For information about custom transformations, see:
https://jestjs.io/docs/code-transformation
Details:
D:\code\chess\chess\node_modules\konva\lib\index-node.js:1
({"Object.<anonymous>":function(module,exports,require,__dirname,__filename,jest){import { Konva } from './_FullInternals.js';
Here is my jest.config.js that worked for me with ts-jest:
/** #type {import('ts-jest/dist/types').InitialOptionsTsJest} */
module.exports = {
preset: 'ts-jest',
testEnvironment: 'jsdom',
moduleNameMapper: {
'^konva': 'konva/konva',
},
globals: {
'ts-jest': {
diagnostics: false,
useESM: true,
},
},
};
I'm using Next.js, and I setup Jest using the official instructions. However, when I run a test for a component that uses the remark module, I get the following error:
Jest encountered an unexpected token
Jest failed to parse a file. This happens e.g. when your code or its dependencies use non-standard JavaScript syntax, or when Jest is not configured to support such syntax.
Out of the box Jest supports Babel, which will be used to transform your files into valid JS based on your Babel configuration.
By default "node_modules" folder is ignored by transformers.
Here's what you can do:
• If you are trying to use ECMAScript Modules, see https://jestjs.io/docs/ecmascript-modules for how to enable it.
• If you are trying to use TypeScript, see https://jestjs.io/docs/getting-started#using-typescript
• To have some of your "node_modules" files transformed, you can specify a custom "transformIgnorePatterns" in your config.
• If you need a custom transformation specify a "transform" option in your config.
• If you simply want to mock your non-JS modules (e.g. binary assets) you can stub them out with the "moduleNameMapper" config option.
You'll find more details and examples of these config options in the docs:
https://jestjs.io/docs/configuration
For information about custom transformations, see:
https://jestjs.io/docs/code-transformation
Details:
/Users/mk/Code/github/hollowverse/hollowverse/node_modules/remark/index.js:1
({"Object.<anonymous>":function(module,exports,require,__dirname,__filename,jest){import {unified} from 'unified'
^^^^^^
SyntaxError: Cannot use import statement outside a module
1 | import matter from 'gray-matter';
> 2 | import { remark } from 'remark';
| ^
3 | import remarkHtml from 'remark-html';
4 | import { sanityClient } from '~/lib/components/sanityio';
5 | import { groqRelatedPeople } from '~/lib/[celeb]/getStaticProps/groqRelatedPeople';
at Runtime.createScriptFromCode (node_modules/jest-runtime/build/index.js:1728:14)
at Object.<anonymous> (lib/[celeb]/getStaticProps/getParsedOldContent.ts:2:32)
My jest.config.js is the following
// jest.config.js
const tsconfig = require('./tsconfig.json');
const moduleNameMapper = require('tsconfig-paths-jest')(tsconfig);
const nextJest = require('next/jest');
const createJestConfig = nextJest({
// Provide the path to your Next.js app to load next.config.js and .env files in your test environment
dir: './',
});
// Add any custom config to be passed to Jest
const customJestConfig = {
// Add more setup options before each test is run
// setupFilesAfterEnv: ['<rootDir>/jest.setup.js'],
// if using TypeScript with a baseUrl set to the root directory then you need the below for alias' to work
moduleDirectories: ['node_modules', '<rootDir>/'],
testEnvironment: 'jest-environment-jsdom',
moduleNameMapper: {
...moduleNameMapper,
'^lodash-es$': 'lodash',
},
};
// createJestConfig is exported this way to ensure that next/jest can load the Next.js config which is async
module.exports = createJestConfig(customJestConfig);
Anyone know how to solve this problem?
I also encountered the same error while setting up Jest in my React app created using Webpack. I had to add #babel/preset-env and it was fixed. I have also written a blog article about the same.
{
"presets": ["#babel/react", "#babel/env"]
}
I am writing the unit tests for my JavaScript/ React JS application using Jest testing framework. When I run my test I am getting the following error.
● Test suite failed to run
Jest encountered an unexpected token
This usually means that you are trying to import a file which Jest cannot parse, e.g. it's not plain JavaScript.
By default, if Jest sees a Babel config, it will use that to transform your files, ignoring "node_modules".
Here's what you can do:
• If you are trying to use ECMAScript Modules, see https://jestjs.io/docs/en/ecmascript-modules for how to enable it.
• To have some of your "node_modules" files transformed, you can specify a custom "transformIgnorePatterns" in your config.
• If you need a custom transformation specify a "transform" option in your config.
• If you simply want to mock your non-JS modules (e.g. binary assets) you can stub them out with the "moduleNameMapper" config option.
You'll find more details and examples of these config options in the docs:
https://jestjs.io/docs/en/configuration.html
Details:
C:\Users\{user}\{project}\app\node_modules\react-date-picker\node_modules\react-calendar\dist\Calendar.css:1
({"Object.<anonymous>":function(module,exports,require,__dirname,__filename,global,jest){.react-calendar {
The error is coming from the package in the node_modules folder, \react-date-picker.
So to fix that, I changed the jest.config.js file as follow.
const esModules = [ 'react-date-picker'].join('|');
module.exports = {
verbose: true,
transformIgnorePatterns: [`/node_modules/(?!${esModules})`]
};
This is the command for the "npm run unit:test"
"jest --watchAll --testPathPattern=tests/unit --config jest.config.js",
When I run the test again, I am still getting the same error. How can I fix it?
A pretty similar case here, he managed to fix it by adding "allowJs": true to the compilerOptions of each lib/app's tsconfig.spec.json (or alternatively to the root tsconfig.json) in addition to setting transformIgnorePatterns.
See source: https://github.com/nrwl/nx/issues/812
I am using create-react-app. Running jest from the CLI causes this error (though in VS Code it shows in my test file that my test passes):
(base) ➜ component-library git:(setup) ✗ jest
FAIL src/App.test.js
● Test suite failed to run
Jest encountered an unexpected token
This usually means that you are trying to import a file which Jest cannot parse, e.g. it's not plain JavaScript.
By default, if Jest sees a Babel config, it will use that to transform your files, ignoring "node_modules".
Here's what you can do:
• If you are trying to use ECMAScript Modules, see https://jestjs.io/docs/en/ecmascript-modules for how to enable it.
• To have some of your "node_modules" files transformed, you can specify a custom "transformIgnorePatterns" in your config.
• If you need a custom transformation specify a "transform" option in your config.
• If you simply want to mock your non-JS modules (e.g. binary assets) you can stub them out with the "moduleNameMapper" config option.
You'll find more details and examples of these config options in the docs:
https://jestjs.io/docs/en/configuration.html
Details:
/Users/Me/go/src/gitlab.com/tensile-payments/component-library/src/setupTests.js:5
import '#testing-library/jest-dom';
^^^^^^
SyntaxError: Cannot use import statement outside a module
at Runtime.createScriptFromCode (node_modules/jest-runtime/build/index.js:1350:14)
My setupTests.js file looks like this:
// jest-dom adds custom jest matchers for asserting on DOM nodes.
// allows you to do things like:
// expect(element).toHaveTextContent(/react/i)
// learn more: https://github.com/testing-library/jest-dom
import '#testing-library/jest-dom';
import Enzyme from 'enzyme';
import Adapter from '#wojtekmaj/enzyme-adapter-react-17';
Enzyme.configure({ adapter: new Adapter() });
I understand from another question's answer that Jest Babel-transforms files before running tests, which should get rid of these import statements. I haven't ejected and so haven't changed the babel config. Other people had the issue that node modules weren't being transformed because the default config excludes them, but this error isn't coming from a node module. How can I fix this?
I fixed it by running tests with npm run test instead of jest, as well as removing
"jest": {
"setupFilesAfterEnv": [
"<rootDir>src/setupTests.js"
]
}
from my package.json (though Enzyme instructs to include it when using Jest).