Jest encountered an unexpected token

[dulx98]

Hi guys!

The library is amazing. Thank you ️☺️!

I am using Jest + React Native + TypeScript to write test cases for my application.

Error:

I got 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:

    <ROOT_DIR>/node_modules/react-native-responsive-screen/index.js:2
    import { Dimensions, PixelRatio } from 'react-native';
    ^^^^^^

    SyntaxError: Cannot use import statement outside a module

    > | import { heightPercentageToDP } from "react-native-responsive-screen";

Environment

Here is my package.json:

"react": "17.0.2",
"react-native": "0.67.2",
"typescript": "^4.4.4"
"react-native-responsive-screen": "^1.4.2",

"@testing-library/jest-native": "^4.0.4",
"@testing-library/react-native": "^9.1.0",
"@types/jest": "^27.5.0",
"jest": "^28.1.0",
"ts-jest": "^28.0.2"

Here is my jest.config.js:

/*
 * For a detailed explanation regarding each configuration property, visit:
 * https://jestjs.io/docs/configuration
 */

module.exports = {
  // Indicates whether the coverage information should be collected while executing the test
  collectCoverage: true,

  // The directory where Jest should output its coverage files
  coverageDirectory: 'coverage',

  // A preset that is used as a base for Jest's configuration
  preset: 'react-native',
}

Preproduce

__tests__/demo.test.tsx

import { render } from "@testing-library/react-native";
import * as React from "react";
import MyComponent from "../src/components/MyComponent";

it("test MyComponent", () => {
  const { getByTestId } = render(<MyComponent />);
});

src/components/MyComponent

import * as React from 'react';
import {Text, View} from 'react-native';
import {heightPercentageToDP} from 'react-native-responsive-screen';

const MyComponent = () => {
   return (
    <View style={{flex: heightPercentageToDP('123')}}>
      <Text>Demo</Text>
    </View>
  );
};
export default MyComponent;

[raazatul7]

Any update on this?

[thtRajasthaniGuy]

+1

[pratikdonda]

+1