Related
In React components importing assets
(ex, import logo from "../../../assets/img/logo.png)
gives such error
({"Object.":function(module,exports,require,__dirname,__filename,global,jest){�PNG
SyntaxError: Invalid or unexpected token
at ScriptTransformer._transformAndBuildScript (node_modules/jest-runtime/build/script_transformer.js:305:17)
my jest config is
"jest": {
"testRegex": ".*\\.spec\\.js$",
"moduleFileExtensions": [
"js",
"jsx",
"json"
],
"moduleDirectories": [
"node_modules",
"src",
"assets"
],
"moduleNameMapper": {
"\\.(jpg|jpeg|png|gif|eot|otf|webp|svg|ttf|woff|woff2|mp4|webm|wav|mp3|m4a|aac|oga)$/": "<rootDir>/__mocks__/fileMock.js",
"\\.(css|less|scss)$": "<rootDir>/__mocks__/styleMock.js"
},
"verbose": true,
"bail": true
}
what am i missing?
When you import image files, Jest tries to interpret the binary codes of the images as .js, hence runs into errors.
The only way out is to mock a default response anytime jest sees an image import!
How do we do this?
first you tell Jest to run the mock file each time an image import is encountered. you do this by adding the key below to your package.json file
"jest": {
"moduleNameMapper": {
"\\.(jpg|ico|jpeg|png|gif|eot|otf|webp|svg|ttf|woff|woff2|mp4|webm|wav|mp3|m4a|aac|oga)$": "<rootDir>/mocks/fileMock.js",
"\\.(css|less)$": "<rootDir>/mocks/fileMock.js"
}
}
Note: if you already have the "Jest" key, just add the "moduleNameMapper" child in it
lastly, create a mocks folder in your root and create fileMock.js file inside it. populate the file with the snippet below
module.exports = '';
Note: If you are using es6 you can use export default ''; to avoid an Eslint flag
when you are done with the above steps, you can restart the test and you are good to go.
Note. remember to add the varying extensions of your image files in the moduleNameMapper so that they can be mocked.
I hope I have been able to help. #cheers!
For anyone looking into this problem. You have to do install npm install --save-dev identity-obj-proxy to get the necessary dependencies.
"jest": {
"moduleNameMapper": {
".+\\.(css|styl|less|sass|scss|png|jpg|ttf|woff|woff2)$": "identity-obj-proxy"
}
}
I had the same problem and I solved it as follows:
npm install -D jest-transform-stub
Then, in package.json, I added the following transformation:
"jest": {
...
"transform": {
...
".+\\.(css|scss|png|jpg|svg)$": "jest-transform-stub"
I had this same issue! I'm not sure if it's the same case as in the original question, but for me jest was still somehow trying to load the images as JS and trying to parse them while I had the files matching image extensions mapped to a mock in moduleNameMapper. My file also included some code to map the # character to the root src directory, since I had webpack and this was configured as a webpack alias in the project (and in TS). The full moduleNameMapper entry in jest.config.js looked like this for me:
moduleNameMapper: {
'^#$': '<rootDir>/src',
'^#/(.*)':
'<rootDir>/src/$1',
'\\.(jpg|jpeg|png|gif|eot|otf|webp|svg|ttf|woff|woff2|mp4|webm|wav|mp3|m4a|aac|oga)$':
'<rootDir>/__mocks__/fileMock.js',
// '\\.(css|less)$': '<rootDir>/__mocks__/styleMock.js',
'.*\\.(css|less)$': 'identity-obj-proxy',
}
For me it turned out that when I was importing the images in my components, the path was something like: '#/assets/someImage.jpg'. However, it seems this would match the first regex first, the one covering the # alias: ^#/(.*). Thus, it was being mapped to <rootDir>/src/$1 instead of the <rootDir>/__mocks__/fileMock.js.
I fixed it by making the alias only match non-images:
moduleNameMapper: {
'^#$': '<rootDir>/src',
'^#/(.*)\\.(?!jpg|jpeg|png|gif|eot|otf|webp|svg|ttf|woff|woff2|mp4|webm|wav|mp3|m4a|aac|oga)$':
'<rootDir>/src/$1',
'.*\\.(jpg|jpeg|png|gif|eot|otf|webp|svg|ttf|woff|woff2|mp4|webm|wav|mp3|m4a|aac|oga)$':
'<rootDir>/__mocks__/fileMock.js',
// '\\.(css|less)$': '<rootDir>/__mocks__/styleMock.js',
'.*\\.(css|less)$': 'identity-obj-proxy',
}
Adding bellow line into jest.config.js file helped me to test pass,
"\\.(jpg|jpeg|png)$": "identity-obj-proxy",
Example:
moduleNameMapper: {
"\\.(css)$": "identity-obj-proxy",
"\\.(jpg|jpeg|png)$": "identity-obj-proxy",
},
If you want to use jest with webpack, you need to explicitly configure it as so. Take a look at this guide here: https://jestjs.io/docs/webpack
For those who use Vue test util in Nuxt 2 and are faced with question or this problem ({"Object.<anonymous>":function(module,exports,require,__dirname,__filename,jest){ SyntaxError: Invalid or unexpected token
make a file with the name of fileTransformer.js in the test/unit directory, and then add these codes:
const path = require('path')
module.exports = {
process(src, filename, config, options) {
return 'module.exports = ' + JSON.stringify(path.basename(filename)) + ';'
},
}
and then add these codes to jest.config.js file:
transform: {
'\\.(jpg|jpeg|png|gif|eot|otf|webp|svg|ttf|woff|woff2|mp4|webm|wav|mp3|m4a|aac|oga)$':
'<rootDir>/test/unit/fileTransformer.js',
// ... other configs
},
In case of IOS image names with #
moduleNameMapper: {
"^image![a-zA-Z0-9$_-]+$": "GlobalImageStub",
"^[#./a-zA-Z0-9$_-]+\\.(png|gif)$": "RelativeImageStub"
}
In React Native we use preset: 'react-native'
https://github.com/facebook/react-native/blob/main/jest-preset.js
Or add transform into jest.config.js
transform: {
'^.+\\.(js|ts|tsx)$': 'babel-jest',
'^.+\\.(bmp|gif|jpg|jpeg|mp4|png|psd|svg|webp)$': require.resolve(
'../node_modules/react-native/jest/assetFileTransformer.js',
),
},
If you do not use React Native, need to create a file https://github.com/facebook/react-native/blob/main/jest/assetFileTransformer.js into your project and changes path into require.resolve
Nothing has worked for me, so I replaced
the 'mount' with 'shallow' everywhere and it's working fine now.
npm install --save-dev identity-obj-proxy
and add the following inside your jest.config.js :
moduleNameMapper: {
"\\.(css)$": "identity-obj-proxy",
"\\.(jpg|jpeg|png)$": "identity-obj-proxy",
},
this worked for me .
I have a React application (not using Create React App) built using TypeScript, Jest, Webpack, and Babel. When trying to run yarn jest, I get the following error:
I have tried removing all packages and re-adding them. It does not resolve this. I have looked at similar questions and documentation and I am still misunderstanding something. I went so far as to follow another guide for setting up this environment from scratch and still received this issue with my code.
Dependencies include...
"dependencies": {
"#babel/plugin-transform-runtime": "^7.6.2",
"#babel/polyfill": "^7.6.0",
"babel-jest": "^24.9.0",
"react": "^16.8.6",
"react-dom": "^16.8.6",
"react-test-renderer": "^16.11.0",
"source-map-loader": "^0.2.4"
},
"devDependencies": {
"#babel/core": "^7.6.0",
"#babel/preset-env": "^7.6.0",
"#babel/preset-react": "^7.0.0",
"#types/enzyme": "^3.9.2",
"#types/enzyme-adapter-react-16": "^1.0.5",
"#types/jest": "^24.0.13",
The component's import lines...
import * as React from "react";
import { BrowserRouter as Router, Route, Switch } from "react-router-dom";
import HomePage from "./components/pages";
import {
Footer,
Header,
Navigation,
} from "./components/shared";
The test file....
import * as React from "react";
import * as renderer from "react-test-renderer";
import App from "../App";
it("Renders the Footer correctly", () => {
const tree = renderer
.create(<App />)
.toJSON();
expect(tree).toMatchSnapshot();
});
I expected to be able to use named imports in my components without my tests blowing up. It appears to fix the issue if I only use default imports through my solution, but I would prefer to not go that route.
Also using Babel, Typescript and Jest. Had the same failure, driving me crazy for hours.
Ended up creating a new babel.config.js file specifically for the tests. Had a large .babelrc that wasn't getting picked up by jest no matter what i did to it. Main app still uses the .babelrc as this overrides babel.config.js files.
Install jest, ts-jest and babel-jest:
npm i jest ts-jest babel-jest
babel.config.js (only used by jest)
module.exports = {presets: ['#babel/preset-env']}
jest.config.js
module.exports = {
preset: 'ts-jest',
transform: {
'^.+\\.(ts|tsx)?$': 'ts-jest',
"^.+\\.(js|jsx)$": "babel-jest",
}
};
package.json
"scripts": {
"test": "jest"
Use Babel to transpile those JS Modules and you'll be able to write your tests with es6.
Install Babel/preset-env
npm i -D #babel/preset-env
Create a babel configuration file with the preset
//babel.config.js
module.exports = {presets: ['#babel/preset-env']}
I solved this by migrating the .babelrc file to babel.config.js! Shocker.
For future references,
I solved the problem by using below jest config, after reading Logan Shoemaker's answer.
module.exports = {
verbose: true,
setupFilesAfterEnv: ["<rootDir>src/setupTests.ts"],
moduleFileExtensions: ["js", "jsx", "ts", "tsx"],
moduleDirectories: ["node_modules", "src"],
moduleNameMapper: {
"\\.(css|less|scss)$": "identity-obj-proxy"
},
transform: {
'^.+\\.(ts|tsx)?$': 'ts-jest',
"^.+\\.(js|jsx)$": "babel-jest",
"\\.(jpg|jpeg|png|gif|eot|otf|webp|svg|ttf|woff|woff2|mp4|webm|wav|mp3|m4a|aac|oga)$": "<rootDir>/__mocks__/file.js",
}
};
try this thing if you are using babel 6
Adding #babel/plugin-transform-modules-commonjs in the plugin section of babel.config.js
or
For my case import issue was due to the react file drop by adding that to transformIgnorePatterns
"transformIgnorePatterns": ["/node_modules/(?!react-file-drop)"]
I fixed it by simply appending the pattern after the run statement in package.json runner
{
"scripts": {
...
"test": "react-scripts test --transformIgnorePatterns 'node_modules/(?!my-library-dir)/'"
...
Then, just run npm test
Solution: my named imports were coming from index.js files and I believe ts-jest needed them as index.ts files (I'm using Typescript). If anyone else runs into this error, couldn't hurt to check if you derped your file extensions.
I wasted a lot of time on this, unfortunately, but I learned a lot about webpack configurations and Babel.
Add your test script in package.json with Node experimental feature: --experimental-vm-modules
In this way you won't require babel or other dependencies.
Examples:
"test": "NODE_OPTIONS='--experimental-vm-modules --experimental-specifier-resolution=node' jest"
If you get this error: zsh: command not found: jest, try with node passing jest.js like this:
"test": "NODE_OPTIONS='--experimental-vm-modules --experimental-specifier-resolution=node --trace-warnings' node node_modules/jest/bin/jest.js --detectOpenHandles"
I'm surprised that none of the answers does not give an elegant solution:
jest.config.js
module.exports = {
...,
globals: {
"ts-jest": {
isolatedModules: true,
},
},
};
This compiles each file separately therefore avoiding the no exports issue.
Create .babelrc on the main directory and add this code and install these packages
#babel/core, #babel/preset-env and #babel/preset-react
{
"presets": [
[
"#babel/preset-env",
{
"modules": "commonjs"
}
],
"#babel/preset-react"
]
}
Matching file extensions:
I importing a file named Todo.jsx in the root as ./src/Todo/. Whenever I changed it to Todo.js the problem went away.
Disclaimer: I'm not sure what the requirement is for having your file extension as jsx vs js for your components. It did not effect me at all, but I could imagine it could mess with intellisense or snippets.
For me renaming file to babel.config.js worked.
Here is my config file an NX project using next with Typescript along with Twin-macro
// .babelrc.js >> babel.config.js
module.exports = {
presets: [
[
"#nrwl/react/babel",
{
"runtime": "automatic",
"targets": {
"browsers": [">0.25%", "not dead"]
},
"preset-react": {
runtime: "automatic",
importSource: "#emotion/react",
},
}
],
'#babel/preset-env',
'#emotion/babel-preset-css-prop',
'#babel/preset-typescript'
],
plugins: ['#emotion', 'macros', '#babel/plugin-transform-runtime', 'react-docgen'],
}
Also, please note even updating package.json works,
https://kulshekhar.github.io/ts-jest/docs/getting-started/presets/#basic-usage
// package.json
"jest": {
// Replace `ts-jest` with the preset you want to use
// from the above list
"preset": "ts-jest"
}
I encountered the same problem with Typescript, Jest, and VueJS/VueCli 3. The normal build has no problem. only happens for Jest. I struggled for hours by searching. But no answer actually works. In my case, I have a dependency on my own typescript package which I specific "target": "es6" in the tsconfig.json. That's the root cause. So the solution is simply to change the dependent's (Not the same project) back to es5 tsconfig.json:
{
"compilerOptions": {
"target": "es5",
...
},
...
}
Personnaly I followed #ajwl setup but discovered that jsdom-worker inside setupFiles: section of jest.config.js was triggering that same error. Once removed, my tests were passing.
P.S. my babel.config.js is a bit different, since I have a Vuejs (v2) SPA (bundled with Vitejs):
module.exports = {
plugins: ['#babel/plugin-transform-modules-commonjs'],
presets: [['#babel/preset-env', { targets: { node: 'current' } }]]
}
The problem is likely that jest doesn't support esmodules natively. Which can cause problems if youre typescript target is es6 or greater.
If you are testing the built typescript output, you could simply add a module=commonjs flag while transpiling. That way, your code can run with es6 or greater and still work with Jest.
"scripts": {
"test": tsc --module commonjs && jest {your-output-folder}/
}
What's great about this is that I didn't have to add any additional babel dependencies or special jest runners :)
I solved it by changing my tsconfig.json to a compatible native output
"module": "commonjs", /* Specify module code generation: 'none', 'commonjs', 'amd', 'system', 'umd', 'es2015', 'es2020', or 'ESNext'. */
It is not ideal in every scenario but you might be okay with this.
All I had to do, was simply updating the package #babel/preset-env in the dev dependencies to the latest version
// package.json
"#babel/preset-env": "^7.18.6"
None of the answers helped me, what did help me was making sure my NODE_ENV was set to test, since babel config is per NODE_ENV using the wrong NODE_ENV by accident that is not configured in babel config will mean you wont be using babel and the typescript files will not be transformed.
It took me couple of hours to figure this one out so i hope it will save someone else the time it took me.
Don't know why and how but how I solved the problem was really interesting.
Just add __mocks__ folder in your src folder and create an empty file inside __mocks__ named axios.js
I discovered that this error might be triggered when you try to load a dependency that is made for the browser and, thus, cannot work with jest (node).
I had a lot of trouble solving this issue for #zip.js/zip.js lib. But I could do it like that:
Here is my jest.config.js. Adapt it to your need. The trick here is the moduleNameMapper that will make all imports to zip.js point to the file __mocks__/#zip.js/zip.js I created in my root folder.
export default {
preset: 'ts-jest',
testEnvironment: 'node',
moduleNameMapper: {
'#zip.js/zip.js': '<rootDir>/__mocks__/#zip.js/zip.js',
},
}
And here is what I have in <rootDir>/__mocks__/#zip.js/zip.js file:
module.exports = {}
Too late for this answer :)
After trying all the possible solutions, this worked for me:
The solution, that works for me:
create a file named jest/mocks/#react-native-firebase/crashlytics.js
export default () => ({ log: jest.fn(), recordError: jest.fn(), });
create a file named jest/jestSetupFile.js
import mockFirebaseCrashlytics from './mocks/#react-native-firebase/crashlytics';
jest.mock('#react-native-firebase/crashlytics', () => mockFirebaseCrashlytics);
in package.json add
"jest": { "setupFiles": ["./jest/jestSetupFile.js"] },
I needed to do a couple things to get this to work for me
Rename my .babelrc to babel.config.js and make a little change:
// .babelrc
{
"presets": [
[
"#babel/preset-env",
{
"corejs": "3.26",
"useBuiltIns": "usage"
}
],
"#babel/preset-react"
],
...
}
// babel.config.js - This still works fine with webpack
module.exports = {
"presets": [
[
"#babel/preset-env",
{
"corejs": "3.26",
"useBuiltIns": "usage"
}
],
"#babel/preset-react"
],
...
}
Add the following to my jest config file:
{
...
"transformIgnorePatterns": [
"node_modules/(?!(react-leaflet-custom-control)/)"
],
...
}
Where react-leaflet-custom-control was the package causing issues for me.
If you're using TypeScript, and you have a tsconfig.json file, try removing "module": "esnext" if you're using it
Running npm ci fixed this problem for me.
I am converting existing tests to use typescript with ts-jest and I have everything finding all the files but all of the tests fail with the error
FAIL src/components/Buttons/__tests__/index.tsx
● Test suite failed to run
Error: No message was provided
I have no idea what is going on and I can't seem to find anyone who had the same problem by Googling either, which is scary...
package.json with jest config
"jest": {
"globals": {
"ts-jest": {
"tsConfigFile": "<rootDir>/tsconfig.json",
"babelConfig": {
"presets": ["#babel/preset-env", "#babel/preset-react"]
}
}
},
"setupTestFrameworkScriptFile": "<rootDir>/src/setupTests.ts",
"verbose": true,
"transform": {
"^.+\\.tsx?$": "ts-jest"
},
"testRegex": "(/__tests__/.*|(\\.|/)(test|spec))\\.(jsx?|tsx?)$",
"moduleNameMapper": {
"\\.(jpg|jpeg|png|gif|eot|otf|webp|svg|ttf|woff|woff2|mp4|webm|wav|mp3|m4a|aac|oga)$": "<rootDir>/__mocks__/fileMock.js",
"typeface-roboto|\\.(css|less)$": "<rootDir>/__mocks__/styleMock.js"
},
"moduleFileExtensions": [
"ts", "tsx", "js", "jsx", "json", "node"
]
},
example test file...
import React from 'react';
import { shallow } from 'enzyme';
import Account from '../account';
it('renders without crashing', () => {
expect(shallow(<Account />)).toBe(1);
});
I found that adding a tsconfig.json file in my project directory fixed this issue.
My tsconfig.json file didn't need anything special in fact it didn't need anything at all! Simply having a blank tsconfig.json file allowed my tests to run.
I was getting similar error for 3 test suits and one was running perfectly. These were running before code merge. After investigation I found that My components are having AAD authentication and the configuration for the same were missing, which I removed for doing check-in. After adding correct configuration resolved my issue.
for some reason, having my tsconfig in the settings was causing the problem. I put it there even though it was the standard name and place (tsconfig.js in the project root)
as soon as I deleted this, I had more errors in my config to clear, but it got past the error in my question
In React components importing assets
(ex, import logo from "../../../assets/img/logo.png)
gives such error
({"Object.":function(module,exports,require,__dirname,__filename,global,jest){�PNG
SyntaxError: Invalid or unexpected token
at ScriptTransformer._transformAndBuildScript (node_modules/jest-runtime/build/script_transformer.js:305:17)
my jest config is
"jest": {
"testRegex": ".*\\.spec\\.js$",
"moduleFileExtensions": [
"js",
"jsx",
"json"
],
"moduleDirectories": [
"node_modules",
"src",
"assets"
],
"moduleNameMapper": {
"\\.(jpg|jpeg|png|gif|eot|otf|webp|svg|ttf|woff|woff2|mp4|webm|wav|mp3|m4a|aac|oga)$/": "<rootDir>/__mocks__/fileMock.js",
"\\.(css|less|scss)$": "<rootDir>/__mocks__/styleMock.js"
},
"verbose": true,
"bail": true
}
what am i missing?
When you import image files, Jest tries to interpret the binary codes of the images as .js, hence runs into errors.
The only way out is to mock a default response anytime jest sees an image import!
How do we do this?
first you tell Jest to run the mock file each time an image import is encountered. you do this by adding the key below to your package.json file
"jest": {
"moduleNameMapper": {
"\\.(jpg|ico|jpeg|png|gif|eot|otf|webp|svg|ttf|woff|woff2|mp4|webm|wav|mp3|m4a|aac|oga)$": "<rootDir>/mocks/fileMock.js",
"\\.(css|less)$": "<rootDir>/mocks/fileMock.js"
}
}
Note: if you already have the "Jest" key, just add the "moduleNameMapper" child in it
lastly, create a mocks folder in your root and create fileMock.js file inside it. populate the file with the snippet below
module.exports = '';
Note: If you are using es6 you can use export default ''; to avoid an Eslint flag
when you are done with the above steps, you can restart the test and you are good to go.
Note. remember to add the varying extensions of your image files in the moduleNameMapper so that they can be mocked.
I hope I have been able to help. #cheers!
For anyone looking into this problem. You have to do install npm install --save-dev identity-obj-proxy to get the necessary dependencies.
"jest": {
"moduleNameMapper": {
".+\\.(css|styl|less|sass|scss|png|jpg|ttf|woff|woff2)$": "identity-obj-proxy"
}
}
I had the same problem and I solved it as follows:
npm install -D jest-transform-stub
Then, in package.json, I added the following transformation:
"jest": {
...
"transform": {
...
".+\\.(css|scss|png|jpg|svg)$": "jest-transform-stub"
I had this same issue! I'm not sure if it's the same case as in the original question, but for me jest was still somehow trying to load the images as JS and trying to parse them while I had the files matching image extensions mapped to a mock in moduleNameMapper. My file also included some code to map the # character to the root src directory, since I had webpack and this was configured as a webpack alias in the project (and in TS). The full moduleNameMapper entry in jest.config.js looked like this for me:
moduleNameMapper: {
'^#$': '<rootDir>/src',
'^#/(.*)':
'<rootDir>/src/$1',
'\\.(jpg|jpeg|png|gif|eot|otf|webp|svg|ttf|woff|woff2|mp4|webm|wav|mp3|m4a|aac|oga)$':
'<rootDir>/__mocks__/fileMock.js',
// '\\.(css|less)$': '<rootDir>/__mocks__/styleMock.js',
'.*\\.(css|less)$': 'identity-obj-proxy',
}
For me it turned out that when I was importing the images in my components, the path was something like: '#/assets/someImage.jpg'. However, it seems this would match the first regex first, the one covering the # alias: ^#/(.*). Thus, it was being mapped to <rootDir>/src/$1 instead of the <rootDir>/__mocks__/fileMock.js.
I fixed it by making the alias only match non-images:
moduleNameMapper: {
'^#$': '<rootDir>/src',
'^#/(.*)\\.(?!jpg|jpeg|png|gif|eot|otf|webp|svg|ttf|woff|woff2|mp4|webm|wav|mp3|m4a|aac|oga)$':
'<rootDir>/src/$1',
'.*\\.(jpg|jpeg|png|gif|eot|otf|webp|svg|ttf|woff|woff2|mp4|webm|wav|mp3|m4a|aac|oga)$':
'<rootDir>/__mocks__/fileMock.js',
// '\\.(css|less)$': '<rootDir>/__mocks__/styleMock.js',
'.*\\.(css|less)$': 'identity-obj-proxy',
}
Adding bellow line into jest.config.js file helped me to test pass,
"\\.(jpg|jpeg|png)$": "identity-obj-proxy",
Example:
moduleNameMapper: {
"\\.(css)$": "identity-obj-proxy",
"\\.(jpg|jpeg|png)$": "identity-obj-proxy",
},
If you want to use jest with webpack, you need to explicitly configure it as so. Take a look at this guide here: https://jestjs.io/docs/webpack
For those who use Vue test util in Nuxt 2 and are faced with question or this problem ({"Object.<anonymous>":function(module,exports,require,__dirname,__filename,jest){ SyntaxError: Invalid or unexpected token
make a file with the name of fileTransformer.js in the test/unit directory, and then add these codes:
const path = require('path')
module.exports = {
process(src, filename, config, options) {
return 'module.exports = ' + JSON.stringify(path.basename(filename)) + ';'
},
}
and then add these codes to jest.config.js file:
transform: {
'\\.(jpg|jpeg|png|gif|eot|otf|webp|svg|ttf|woff|woff2|mp4|webm|wav|mp3|m4a|aac|oga)$':
'<rootDir>/test/unit/fileTransformer.js',
// ... other configs
},
In case of IOS image names with #
moduleNameMapper: {
"^image![a-zA-Z0-9$_-]+$": "GlobalImageStub",
"^[#./a-zA-Z0-9$_-]+\\.(png|gif)$": "RelativeImageStub"
}
In React Native we use preset: 'react-native'
https://github.com/facebook/react-native/blob/main/jest-preset.js
Or add transform into jest.config.js
transform: {
'^.+\\.(js|ts|tsx)$': 'babel-jest',
'^.+\\.(bmp|gif|jpg|jpeg|mp4|png|psd|svg|webp)$': require.resolve(
'../node_modules/react-native/jest/assetFileTransformer.js',
),
},
If you do not use React Native, need to create a file https://github.com/facebook/react-native/blob/main/jest/assetFileTransformer.js into your project and changes path into require.resolve
Nothing has worked for me, so I replaced
the 'mount' with 'shallow' everywhere and it's working fine now.
npm install --save-dev identity-obj-proxy
and add the following inside your jest.config.js :
moduleNameMapper: {
"\\.(css)$": "identity-obj-proxy",
"\\.(jpg|jpeg|png)$": "identity-obj-proxy",
},
this worked for me .
I am trying to get my first Jest Test to pass with React and Babel.
I am getting the following error:
SyntaxError: /Users/manueldupont/test/avid-sibelius-publishing-viewer/src/components/TransportButton/TransportButton.less: Unexpected token
> 7 | #import '../variables.css';
| ^
My package.json config for jest look like this:
"babel": {
"presets": [
"es2015",
"react"
],
"plugins": [
"syntax-class-properties",
"transform-class-properties"
]
},
"jest": {
"moduleNameMapper": {
"^image![a-zA-Z0-9$_-]+$": "GlobalImageStub",
"^[./a-zA-Z0-9$_-]+\\.png$": "RelativeImageStub"
},
"testPathIgnorePatterns": [
"/node_modules/"
],
"collectCoverage": true,
"verbose": true,
"modulePathIgnorePatterns": [
"rpmbuild"
],
"unmockedModulePathPatterns": [
"<rootDir>/node_modules/react/",
"<rootDir>/node_modules/react-dom/",
"<rootDir>/node_modules/react-addons-test-utils/",
"<rootDir>/node_modules/fbjs",
"<rootDir>/node_modules/core-js"
]
},
So what am I missing?
moduleNameMapper is the setting that tells Jest how to interpret files with different extension. You need to tell it how to handle Less files.
Create a file like this in your project (you can use a different name or path if you’d like):
config/CSSStub.js
module.exports = {};
This stub is the module we will tell Jest to use instead of CSS or Less files. Then change moduleNameMapper setting and add this line to its object to use it:
'^.+\\.(css|less)$': '<rootDir>/config/CSSStub.js'
Now Jest will treat any CSS or Less file as a module exporting an empty object. You can do something else too—for example, if you use CSS Modules, you can use a Proxy so every import returns the imported property name.
Read more in this guide.
I solved this by using the moduleNameMapper key in the jest configurations in the package.json file
{
"jest":{
"moduleNameMapper":{
"\\.(css|less|sass|scss)$": "<rootDir>/__mocks__/styleMock.js",
"\\.(gif|ttf|eot|svg)$": "<rootDir>/__mocks__/fileMock.js"
}
}
}
After this you will need to create the two files as described below
__mocks__/styleMock.js
module.exports = {};
__mocks__/fileMock.js
module.exports = 'test-file-stub';
If you are using CSS Modules then it's better to mock a proxy to enable className lookups.
hence your configurations will change to:
{
"jest":{
"moduleNameMapper": {
"\\.(jpg|jpeg|png|gif|eot|otf|webp|svg|ttf|woff|woff2|mp4|webm|wav|mp3|m4a|aac|oga)$": "<rootDir>/__mocks__/fileMock.js",
"\\.(css|less|scss|sass)$": "identity-obj-proxy"
},
}
}
But you will need to install identity-obj-proxy package as a dev dependancy i.e.
yarn add identity-obj-proxy -D
For more information. You can refer to the jest docs
UPDATE who use create-react-app from feb 2018.
You cannot override the moduleNameMapper in package.json but in jest.config.js it works, unfortunately i havent found any docs about this why it does.
So my jest.config.js look like this:
module.exports = {
...,
"moduleNameMapper": {
"\\.(jpg|jpeg|png|gif|eot|otf|webp|svg|ttf|woff|woff2|mp4|webm|wav|mp3|m4a|aac|oga)$": "<rootDir>/__mocks__/fileMock.js",
"\\.(scss|sass|css)$": "identity-obj-proxy"
}
}
and it skips scss files and #import quite well.
Backing my answer i followed jest webpack
Similar situation, installing identity-object-proxy and adding it to my jest config for CSS is what worked for me.
//jest.config.js
module.exports = {
moduleNameMapper: {
"\\.(css|sass)$": "identity-obj-proxy",
},
};
The specific error I was seeing:
Jest encountered an unexpected token
/Users/foo/projects/crepl/components/atoms/button/styles.css:1
({"Object.<anonymous>":function(module,exports,require,__dirname,__filename,global,jest){.button { }
^
SyntaxError: Unexpected token .
1 | import React from 'react';
> 2 | import styles from './styles.css';
If you're using ts-jest, none of the solutions above will work! You'll need to mock transform.
jest.config.js
module.exports = {
preset: 'ts-jest',
testEnvironment: 'jsdom',
roots: [
"<rootDir>/src"
],
transform: {
".(jpg|jpeg|png|gif|eot|otf|webp|svg|ttf|woff|woff2|mp4|webm|wav|mp3|m4a|aac|oga)$": "<rootDir>/jest-config/file-mock.js",
'.(css|less)$': '<rootDir>/jest-config/style-mock.js'
},
};
file-mock.js
module.exports = {
process() {
return `module.exports = 'test-file-stub'`;
},
};
style-mock.js
module.exports = {
process() {
return 'module.exports = {};';
}
};
I found this working example if you want more details.
Solution of #import Unexpected token=:)
Install package:
npm i --save-dev identity-obj-proxy
Add in jest.config.js
module.exports = {
"moduleNameMapper": {
"\\.(css|less|scss)$": "identity-obj-proxy"
}
}
Update: Aug 2021
If you are using Next JS with TypeScript. Simply follow the examples repo.
Else you will be wasting days configuring the environment.
https://github.com/vercel/next.js/tree/canary/examples/with-jest
I added moduleNameMapper at the bottom of my package.json where I configured my jest just like this:
"jest": {
"verbose": true,
"moduleNameMapper": {
"\\.(scss|less)$": "<rootDir>/config/CSSStub.js"
}
}