I followed the Jest - React tutorial to test a React component.
Unfortunately, Jest throws:
SyntaxError: /Users/mishamoroshko/react-playground/src/search-panel/questions/__tests__/questions-test.js: /Users/mishamoroshko/react-playground/src/search-panel/questions/questions.js: Unexpected token ILLEGAL
at Contextify.sandbox.run (/Users/mishamoroshko/react-playground/node_modules/jest-cli/node_modules/jsdom/node_modules/contextify/lib/contextify.js:12:24)
at JSDomEnvironment.runSourceText (/Users/mishamoroshko/react-playground/node_modules/jest-cli/src/JSDomEnvironment.js:108:22)
at Object.runContentWithLocalBindings (/Users/mishamoroshko/react-playground/node_modules/jest-cli/src/lib/utils.js:341:23)
To reproduce:
git clone git#github.com:SEEK-Jobs/react-playground.git
cd react-playground
npm install
npm test
Any ideas?
UPDATE 1:
I wonder whether the problem is that Jest doesn't know about ES6, and I need to use 6to5-jest.
Is there a way to specify 2 preprocessors in package.json?
"jest": {
"rootDir": "src",
"scriptPreprocessor": "../preprocessor.js",
"unmockedModulePathPatterns": [
"../node_modules/react"
]
}
Indeed, adding 6to5-jest solved the problem.
Here is how I implemented multiple scriptPreprocessors in Jest:
// preprocessor.js
var ReactTools = require('react-tools');
var to5 = require('6to5-jest').process;
module.exports = {
process: function(src, filename) {
return ReactTools.transform(to5(src, filename));
}
};
If you have a better way to implement this, please leave a comment.
Related
The development environment uses next.js 13.
After updating the query-string library to 8.1, test:ci now fails.
It fails at the following point.
before "query-string": "^7.1.0",
after "query-string": "^8.1.0",
error
({"Object.<anonymous>":function(module,exports,require,__dirname,__filename,jest){import * as queryString from './base.js';
^^^^^^
SyntaxError: Cannot use import statement outside a module
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.
Changed part.
before
import { stringifyUrl } from 'query-string';
.
. omission
.
stringifyUrl({url})
after
import queryString from 'query-string';
.
.　omission
.
queryString.stringifyUrl({ url })
I am very troubled.
If anyone knows how to solve this problem, please let me know.
added
module.exports = {
setupFilesAfterEnv: ['<rootDir>/jest.setup.ts'],
collectCoverageFrom: ['src/**/*.{js,jsx,ts,tsx}', '!**/*.d.ts'],
moduleDirectories: ['node_modules', 'src'],
moduleNameMapper: {
// Handle CSS imports (with CSS modules)
// https://jestjs.io/docs/webpack#mocking-css-modules
'^.+\\.module\\.(css|sass|scss)$': 'identity-obj-proxy',
// Handle CSS imports (without CSS modules)
'^.+\\.(css|sass|scss)$': '<rootDir>/src/__mocks__/styleMock.ts',
// Handle image imports
// https://jestjs.io/docs/webpack#handling-static-assets
'^.+\\.(png|jpg|jpeg|gif|webp|avif|ico|bmp|svg)$/i': `<rootDir>/src/__mocks__/fileMock.ts`,
// Handle ESM packages
'^react-markdown$': '<rootDir>/src/__mocks__/react-markdown.tsx',
},
testPathIgnorePatterns: ['<rootDir>/node_modules/', '<rootDir>/.next/'],
testEnvironment: 'jest-environment-jsdom',
transform: {
// Use babel-jest to transpile tests with the next/babel preset
// https://jestjs.io/docs/configuration#transform-objectstring-pathtotransformer--pathtotransformer-object
'^.+\\.(js|jsx|ts|tsx)$': ['babel-jest', { presets: ['next/babel'] }],
},
transformIgnorePatterns: [
'/node_modules/',
'^.+\\.module\\.(css|sass|scss)$',
],
};
The issue is query-string version 8 introduced a breaking to consuming applications because their dependencies upgraded to ESM. See their release notes here:
v8.0.0
Breaking
Require Node.js 14
This package is now pure ESM. Please read this.
Add "module": "node16", "moduleResolution": "node16" to your
tsconfig.json.
(Example)
And more!!!
It appears Jest in trying to use import but it's not configured to do so. Jest also provides some guidance for how to deal with this: https://jestjs.io/docs/ecmascript-modules
Since you're using Next.js, those steps don't really apply.
I'm reproducing and testing in a sandbox... Will update shorty.
For React apps:
Try setting "type": "module" inside package.json.
You should also update your package.json test script to:
"test": "node --experimental-vm-modules ./node_modules/.bin/jest"
Now inside jest.config.js you'll want to export transform: {}:
export default {
transform: {}
}
After all those steps, you should no longer have this issue.
I am currently having trouble with my React TypeScript project.
I created my project with npx create-react-app my-app --template typescript.
I recently added tsyringe for dependency injection and was trying to implement it for an apiService. After following the readme(https://github.com/microsoft/tsyringe#injecting-primitive-values-named-injection) for adding primitive values I have hit a block. I already add experimentalDecorators and emitDecoratorMetadata to my tsconfig.json file with no success.
The error actual error I am encountering is:
./src/ts/utils/NetworkService.ts 9:14
Module parse failed: Unexpected character '#' (9:14)
File was processed with these loaders:
* ./node_modules/#pmmmwh/react-refresh-webpack-plugin/loader/index.js
* ./node_modules/babel-loader/lib/index.js
You may need an additional loader to handle the result of these loaders.
|
| let NetworkService = (_dec = singleton(), _dec(_class = (_temp = class NetworkService {
> constructor(#inject('SpecialString')
| value) {
| this.str = void 0;
I am fairly sure this problem is caused by Babel, however I created this with npm create react-app --template typescript and do not seem to have access to the Babel configuration.
NetworkService.ts
#singleton()
export default class NetworkService
{
private str: string;
constructor(#inject('SpecialString') value: string) {
this.str = value;
}
}
Invocation method
bob()
{
const inst = container.resolve(NetworkService);
}
Registering Class in index.ts
container.register('SpecialString', {useValue: 'https://myme.test'});
#registry([
{ token: NetworkService, useClass: NetworkService },
])
class RegisterService{}
React-Scripts manages many of the configs related to the project. For many cases, this is fine and actually a nice feature. However, because React-Scripts uses Babel for it's development environment and does not expose the config.
You have to run npm run eject to expose the configurations.
Please note, this is a one-way operation and can not be undone.
Personally, I prefer more control with my configuration.
After this you can edit the webpack.config.js in the newly created config folder.
Find the section related to the babel-loader in the dev-environment and add 'babel-plugin-transform-typescript-metadata' to the plugins array.
Expanding on Jordan Schnur's reply, here are some more pitfalls I encountered when adding TSyringe to my CRA app:
Use import type with #inject
If you get this error "TS1272: A type referenced in a decorated signature must be imported with 'import type' or a namespace import when 'isolatedModules' and 'emitDecoratorMetadata' are enabled." replace import with import type for the offending imports. You will encounter this when working with #inject
E.g. replace import { IConfig } from "iconfig" with import type { IConfig } from "iconfig"
Fixing Jest
Your Jest tests will also break with TSyringe, especially when using #inject. I got the error "Jest encountered an unexpected token" with details constructor(#((0, _tsyringe.inject)("")) ("#" marked as the offending token). I took the following steps to fix that in CRA:
Add the line import "reflect-metadata"; to the top of the file src/setupTests.ts
In config/jest/babelTransform.js replace line 18 and following:
From
module.exports = babelJest.createTransformer({
presets: [
[
require.resolve('babel-preset-react-app'),
{
runtime: hasJsxRuntime ? 'automatic' : 'classic',
},
],
],
babelrc: false,
configFile: false,
});
to:
module.exports = babelJest.createTransformer({
presets: [
[
require.resolve('babel-preset-react-app'),
{
runtime: hasJsxRuntime ? 'automatic' : 'classic',
},
],
],
plugins: [
require.resolve('babel-plugin-transform-typescript-metadata')
],
babelrc: false,
configFile: false,
});
Instead of eject, you may use a lib that "overrides" some of your params.
I used craco : https://www.npmjs.com/package/#craco/craco
I've created an simpler DI library that doesn't need decorators or polyfill. Works with CRA like a charm and has cool React bindings
iti
import { useContainer } from "./_containers/main-app"
function Profile() {
const [auth, authErr] = useContainer().auth
if (authErr) return <div>failed to load</div>
if (!auth) return <div>loading...</div>
return <div>hello {auth.profile.name}!</div>
}
I am trying to set up Storybook in a project. My project is runing on react#^16, and I'm using typescript, with a custom babel and webpack setup for development and build. To set up storybook, I did
npx sb init
This installs everything needed. It puts a .storybook folder in the root folder, and a stories folder in my src folder with some prefab components and stories in tsx format (which is what I want):
The .storybook/main.js file seems fine:
module.exports = {
"stories": [
"../src/**/*.stories.mdx",
"../src/**/*.stories.#(js|jsx|ts|tsx)"
],
"addons": [
"#storybook/addon-links",
"#storybook/addon-essentials"
]
}
And the average .stories.js file automatically installed by npx sb init also seems fine:
import React from 'react';
// also exported from '#storybook/react' if you can deal with breaking changes in 6.1
import { Story, Meta } from '#storybook/react/types-6-0';
import { Header, HeaderProps } from './Header';
export default {
title: 'Example/Header',
component: Header,
} as Meta;
const Template: Story<HeaderProps> = (args) => <Header {...args} />;
export const LoggedIn = Template.bind({});
LoggedIn.args = {
user: {},
};
export const LoggedOut = Template.bind({});
LoggedOut.args = {};
But when I run npm run storybook, the storybook landing page has no stories. Even though it had installed some default stories to start playing with. It says:
Oh no! Your Storybook is empty. Possible reasons why:
The glob specified in main.js isn't correct.
No stories are defined in your story files.
As requested, here is a link to the repo so you can dig a bit deeper into the structure, weback config, etc. Note I have not committed the npx sb init changes yet, so you won't see the files there, only my starting point just before running the sb init.
I haven't had any issues getting npx sb init to work with a standard create-react-app, but with my custom webpack build and typescript, its just empty. What's going wrong?
Edit: Additional detail
I realize that just running npx sb init, then npm run storybook throws this error:
ERROR in ./.storybook/preview.js-generated-config-entry.js
Module not found: Error: Can't resolve 'core-js/modules/es.array.filter'
Based on this thread, installing core-js#3 solves the problem and storybook runs, though with no stories.
It seems like the babel plugin transform-es2015-modules-amd doesn't fit right with storybook since sb still uses your babel configuration.
You might need to remove it then it would work:
{
"plugins": [
// "transform-es2015-modules-amd", // Remove this plugin
]
}
If you want to have a special babel configuration for storybook, place it .storybook/.babelrc so the configuration would be simple like this:
.storybook/.babelrc:
{
"presets": ["#babel/preset-env", "#babel/preset-react", "#babel/preset-typescript"]
}
NOTE: You might miss to forget install #babel/preset-typescript to help you transform your typescript code.
Maybe you have problems with the stories path, try to save only "../src/**/*.stories.js" in your config to see if its the reason
"stories": [
"../src/**/*.stories.mdx",
"../src/**/*.stories.#(js|jsx|ts|tsx)"
]
In case of dealing with arcgis-js-api in sb, you have to declare #arcgis/webpack-plugin in storybook's webpack configuration by adding to its config.
Here are a few steps you have to do:
Add webpackFinal property in .storybook/main.js with following content:
const ArcGISPlugin = require('#arcgis/webpack-plugin');
module.exports = {
// ...
webpackFinal: (config) => {
// Add your plugin
config.plugins.push(
new ArcGISPlugin(),
);
// Since this package has used some node's API so you might have to stop using it as client side
config.node = {
...config.node,
process: false,
fs: "empty"
};
return config;
}
};
One more thing to be aware of, some components are importing scss files, so you might need to support it by adding a scss addon '#storybook/preset-scss'
// Install
npm i -D #storybook/preset-scss css-loader sass-loader style-loader
// Add to your current addons
{
addons: ['#storybook/addon-links', '#storybook/addon-essentials', '#storybook/preset-scss'],
}
Like a tmhao2005 say. Storybook still uses your babel configuration. And this is the intended behavior. This thread at github also describes how the fix similar issue.
Updated your config .storybook/main.js.
If you use .babelrc:
babel: async options => ({ ...options, babelrc: false })
Or .babel.config.js:
babel: async options => ({ ...options, configFile: false })
I'm currently importing a module using file loader in one of my files in a react app (CRA):
"file-loader?name=scripts/[name].[hash].js!jsstore/dist/jsstore.worker.min.js"
When running Jest, it throws this error:
Cannot find module 'file-loader?name=scripts/[name].[hash].js!jsstore/dist/jsstore.worker.min.js'
I've attempted different configs in package.json for Jest, by setting either modulePathIgnorePatterns and moduleNameMapper, but neither config setting works:
"modulePathIgnorePatterns": [
"file-loader?name=scripts/[name].[hash].js!jsstore/dist/jsstore.worker.min.js"
]
"moduleNameMapper": {
"file-loader?name=scripts/[name].[hash].js!jsstore/dist/jsstore.worker.min.js": "<rootDir>/node_modules/jsstore/dist/jsstore.worker.min.js"
}
You can map this import to a file that will return a string which what file-loader returns;
moduleNameMapper: {
"^file\-loader":"<rootDir>/__mocks__/fileMock.js",
}
// __mocks__/fileMock.js
module.exports = 'file-path-mock';
I use webpack to develop a React component. Here is a simple version of it:
'use strict';
require('./MyComponent.less');
var React = require('react');
var MyComponent = React.createClass({
render() {
return (
<div className="my-component">
Hello World
</div>
);
}
});
module.exports = MyComponent;
Now, I would like to test this component using jest. Here is the relevant bit from my package.json:
"scripts": {
"test": "jest"
},
"jest": {
"rootDir": ".",
"testDirectoryName": "tests",
"scriptPreprocessor": "<rootDir>/node_modules/babel-jest",
"unmockedModulePathPatterns": [
"react"
]
}
When running npm test, I get the following error:
SyntaxError: /Users/mishamoroshko/react-component/src/tests/MyComponent.js: /Users/mishamoroshko/react-component/src/MyComponent.js: /Users/mishamoroshko/react-component/src/MyComponent.less: Unexpected token ILLEGAL
Looks like webpack needs to process require('./MyComponent.less') before jest can run the test.
I wonder if I need to use something like jest-webpack. If yes, is there a way to specify multiple scriptPreprocessors? (note that I already use babel-jest)
The cleanest solution I found for ignoring a required module is to use the moduleNameMapper config (works on the latest version 0.9.2)
The documentation is hard to follow. I hope the following will help.
Add moduleNameMapper key to your packages.json config. The key for an item should be a regex of the required string. Example with '.less' files:
"moduleNameMapper": { "^.*[.](less|LESS)$": "EmptyModule" },
Add a EmptyModule.js to your root folder:
/**
* #providesModule EmptyModule
*/
module.exports = '';
The comment is important since the moduleNameMapper use EmptyModule as alias to this module (read more about providesModule).
Now each require reference that matches the regex will be replaced with an empty string.
If you use the moduleFileExtensions configuration with a 'js' file, then make sure you also add the EmptyModule to your 'unmockedModulePathPatterns'.
Here is the jest configuration I ended up with:
"jest": {
"scriptPreprocessor": "<rootDir>/node_modules/babel-jest",
"moduleFileExtensions": ["js", "json","jsx" ],
"moduleNameMapper": {
"^.*[.](jpg|JPG|gif|GIF|png|PNG|less|LESS|css|CSS)$": "EmptyModule"
},
"preprocessorIgnorePatterns": [ "/node_modules/" ],
"unmockedModulePathPatterns": [
"<rootDir>/node_modules/react",
"<rootDir>/node_modules/react-dom",
"<rootDir>/node_modules/react-addons-test-utils",
"<rootDir>/EmptyModule.js"
]
}
I ended up with the following hack:
// package.json
"jest": {
"scriptPreprocessor": "<rootDir>/jest-script-preprocessor",
...
}
// jest-script-preprocessor.js
var babelJest = require("babel-jest");
module.exports = {
process: function(src, filename) {
return babelJest.process(src, filename)
.replace(/^require.*\.less.*;$/gm, '');
}
};
But, I'm still wondering what is the right solution to this problem.
I just found that it's even simpler with Jest's moduleNameMapper configuration.
// package.json
"jest": {
"moduleNameMapper": {
"^.+\\.scss$": "<rootDir>/scripts/mocks/style-mock.js"
}
}
// style-mock.js
module.exports = {};
More detail at Jest's tutorial page.
I recently released Jestpack which might help. It first builds your test files with Webpack so any custom module resolution/loaders/plugins etc. just work and you end up with JavaScript. It then provides a custom module loader for Jest which understands the Webpack module runtime.
From Jest docs:
// in terminal, add new dependency: identity-obj-proxy
npm install --save-dev identity-obj-proxy
// package.json (for CSS Modules)
{
"jest": {
"moduleNameMapper": {
"\\.(css|less)$": "identity-obj-proxy"
}
}
}
The snippet above will route all .less files to the new dependency identity-obj-proxy, which will return a string with the classname when invoked, e.g. 'styleName' for styles.styleName.
I think a less hacky solution would be to wrap your preprocessor in a conditional on the filename matching a javascript file:
if (filename.match(/\.jsx?$/)) {
return babelJest.process(src, filename);
} else {
return '';
}
This works even if you don't explicitly set the extension in the require line and doesn't require a regex substitution on the source.
I have experienced similar issue with such pattern
import React, { PropTypes, Component } from 'react';
import styles from './ContactPage.css';
import withStyles from '../../decorators/withStyles';
#withStyles(styles)
class ContactPage extends Component {
see example at https://github.com/kriasoft/react-starter-kit/blob/9204f2661ebee15dcb0b2feed4ae1d2137a8d213/src/components/ContactPage/ContactPage.js#L4-L7
For running Jest I has 2 problems:
import of .css
applying decorator #withStyles (TypeError: <...> (0 , _appDecoratorsWithStyles2.default)(...) is not a function)
First one was solved by mocking .css itself in script preprocessor.
Second one was solved by excluding decorators from automocking using unmockedModulePathPatterns
module.exports = {
process: function (src, filename) {
...
if (filename.match(/\.css$/)) src = '';
...
babel.transform(src, ...
}
}
example based on https://github.com/babel/babel-jest/blob/77a24a71ae2291af64f51a237b2a9146fa38b136/index.js
Note also: when you working with jest preprocessor you should clean cache:
$ rm node_modules/jest-cli/.haste_cache -r
Taking inspiration from Misha's response, I created an NPM package that solves this problem while also handling a few more scenarios I came across:
webpack-babel-jest
Hopefully this can save the next person a few hours.
If you're using babel, you can strip unwanted imports during the babel transform using something like https://github.com/Shyp/babel-plugin-import-noop and configuring your .babelrc test env to use the plugin, like so:
{
"env": {
"development": {
...
},
"test": {
"presets": [ ... ],
"plugins": [
["import-noop", {
"extensions": ["scss", "css"]
}]
]
}
}
}
We had a similar problem with CSS files. As you mentioned before jest-webpack solves this problem fine. You won't have to mock or use any module mappers either. For us we replaced our npm test command from jest to jest-webpack and it just worked.
Webpack is a great tool, but I don't need to test it's behavior with my Jest unit tests, and adding a webpack build prior to running unit tests is only going to slow down the process. The text-book answer is to mock non-code dependencies using the "moduleNameMapper" option
https://facebook.github.io/jest/docs/webpack.html#handling-static-assets