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ViewsHow to resolve "Cannot use import statement outside a module" in jest
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.
3 answers
Answer question0
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"
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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']}
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I solved this by migrating the .babelrc file to babel.config.js! Shocker.