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I am trying to setup test environment for a react project written in typescript. I have done it before for react but with ES6.

Following is how the relevant parts of my package.json look like -

 "scripts": {
    "test": "NODE_ENV=test jest",
    "build": "webpack --mode production",
    "start": "webpack-dev-server --open --mode development"
  },
  "jest": {
    "moduleNameMapper": {
      "\\.(css)$": "jest-css-modules"
    },
    "transform": {
      "\\.(ts|tsx)$": "ts-jest"
    },
    "testRegex": ".test.(ts|tsx?)$",
    "moduleFileExensions": ["ts", "tsx", "js", "jsx", "json", "node"]
  },

I would like to mention that I am counting on ts transpiler and not configured babel at all.

Following are the dependencies I have included -

"dependencies": {
    "@types/jest": "^23.1.4",
    "@types/react": "^16.4.5",
    "@types/react-dom": "^16.0.6",
    "@types/react-redux": "^6.0.3",
    "@types/redux": "^3.6.0",
    "deep-freeze": "0.0.1",
    "jest": "^23.2.0",
    "jest-css-modules": "^1.1.0",
    "react-redux": "^5.0.7",
    "redux": "^4.0.0",
    "ts-jest": "^23.0.0",
    "webpack": "^4.12.2"
  },
  "devDependencies": {
    "awesome-typescript-loader": "^5.2.0",
    "css-loader": "^0.28.11",
    "html-loader": "^0.5.5",
    "html-webpack-plugin": "^3.2.0",
    "prop-types": "^15.6.2",
    "react": "^16.4.1",
    "react-dom": "^16.4.1",
    "style-loader": "^0.21.0",
    "typescript": "^2.9.2",
    "typings-for-css-modules-loader": "^1.7.0",
    "url-loader": "^1.0.1",
    "webpack-cli": "^3.0.8",
    "webpack-dev-server": "^3.1.4"
  }

I am unable to understand following error when I run npm run test as I have already installed and specified ts-jest in transform -

Validation Error:

  Module ts-jest in the transform option was not found.
         <rootDir> is: /Users/rahul/ot/Lab/webpack-playlist

Following is how tsconfig.json looks like

{
  "compilerOptions": {
    "jsx": "react",
    "noImplicitAny": true,
    "sourceMap": true,
    "target": "es5"
  }
}

Not sure how I can I resolve the error above.

I also tried configuring ts-jest in tsconfig.json like below but it still gave same error -

// tsconfig.json
    "jest": {
        "globals": {
          "ts-jest": {
            "tsConfigFile": "tsconfig.jest.json"
          }
        }
      }


// tsconfig.jest.json
{
  "extends": "./tsconfig",
  "compilerOptions": {
    "module": "commonjs"
  }
}

Looking through this, there isnt much that is different from my setup here:

https://github.com/jasonraimondi/typescript-react-starter

There is minor differences in your jest config. Below is the contents of my jest.config.js file.

module.exports = {
  "transform": {
    "^.+\\.tsx?$": "ts-jest"
  },
  "testRegex": "(/__tests__/.*|(\\.|/)(test|spec))\\.(jsx?|tsx?)$",
  "moduleFileExtensions": [
    "ts",
    "tsx",
    "js",
    "jsx",
    "json",
    "node"
  ],
  "setupFiles": [
    "<rootDir>/test/setupTests.ts"
  ]
};

I have a post about testing a Typescript React App using ts-jest without "create-react-app" that hopefully may be of some help to.

11 users liked answer #0dislike answer #011
Jason Raimondi profile pic
Jason Raimondi

Here is an example setup for using Jest in a TypeScript React project. I created it myself and I hope it helps you:

jest.config.js

const {defaults} = require('jest-config');

module.exports = {
  bail: true,
  moduleFileExtensions: [...defaults.moduleFileExtensions, 'ts', 'tsx'],
  roots: ['src'],
  testMatch: ['<rootDir>/src/**/?(*.)test.{ts,tsx}'],
  transform: {
    '^.+\\.tsx?$': 'ts-jest',
  },
  verbose: true,
};

package.json

{
  "dependencies": {
    "@types/react": "16.7.18",
    "@types/react-dom": "16.0.11",
    "react": "16.7.0",
    "react-dom": "16.7.0"
  },
  "devDependencies": {
    "jest": "23.6.0",
    "ts-jest": "23.10.5"
  },
  "scripts": {
    "test": "jest"
  },
  "version": "0.0.0"
}

src/Welcome.tsx

import * as React from 'react';

interface WelcomeProps {
  name: string,
}

const Welcome: React.FunctionComponent<WelcomeProps> = (props: WelcomeProps) => {
  return <h1>Hello, {props.name}</h1>;
};

export default Welcome;

src/Welcome.test.tsx

import React from 'react';
import ReactDOM from 'react-dom';

import Welcome from './Welcome';

it('renders without crashing', () => {
  const div = document.createElement('div');
  ReactDOM.render(<Welcome name="John Doe"/>, div);
  ReactDOM.unmountComponentAtNode(div);
});
2 users liked answer #1dislike answer #12
Benny Neugebauer profile pic
Benny Neugebauer

This is the only configuration that worked for me. Here are my specs:

{
  "name": "project",
  "version": "1.0.0",
  "description": "project",
  "jest": {
    "modulePathIgnorePatterns": [
      "dist/"
    ],
    "snapshotSerializers": [
      "enzyme-to-json/serializer"
    ],
    "moduleNameMapper": {
      "^.+\\.(css|less|scss)$": "identity-obj-proxy"
    },
    "setupFilesAfterEnv": [
      "./setupTests.ts"
    ],
    "coverageReporters": [
      "text",
      "lcov"
    ],
    "coverageDirectory": ".",
    "transform": {
      ".(js|jsx)": "babel-jest",
      ".(ts|tsx)": "ts-jest"
    }
  },
  "peerDependencies": {
    "react": "^16.12.0",
    "react-dom": "^16.12.0"
  },
  "devDependencies": {
    "@types/enzyme": "^3.10.5",
    "@types/enzyme-adapter-react-16": "^1.0.6",
    "@types/jest": "^26.0.4",
    "babel-preset-env": "^1.7.0",
    "babel-preset-react": "^6.24.1",
    "enzyme-adapter-react-16": "^1.12.1",
    "ts-jest": "^26.1.0",
    "typescript": "~3.9.5"
  },
  "scripts": {
    "tsc": "tsc --build tsconfig.json",
    "watch": "tsc --watch",
    "test": "jest",
    "test-coverage": "jest --coverage"
  }
}

setupTests.ts:

import * as Enzyme from 'enzyme';
import * as Adapter from 'enzyme-adapter-react-16';

Enzyme.configure({ adapter: new Adapter() });

And finally here is my tsconfig.json:

{
  "compileOnSave": false,
  "compilerOptions": {
    "allowJs": true,
    "declaration": true,
    "declarationMap": true,
    "jsx": "react",
    "emitDecoratorMetadata": true,
    "experimentalDecorators": true,
    "skipLibCheck": true,
    "noImplicitAny": true,
    "target": "es5",
    "outDir": "./dist",
    "declarationDir": "./dist",
    "lib": ["es2016", "dom"]
  },
  "include": ["./src/index.ts"]
}
1 users liked answer #2dislike answer #21
Melchia profile pic
Melchia

I had same error and got it fixed by running following commands in terminal: Via npm: 1. "npm i -D jest typescript" 2. "npm i -D ts-jest @types/jest " 3. "npx ts-jest config:init" 4. "npm t or npx jest"

Via yarn: 1. "yarn add --dev jest typescript" 2. "yarn add --dev ts-jest @types/jest" 3. "yarn ts-jest config:init" 4. "yarn test or yarn jest"

I am using ubuntu 18.04.3 LTS.

0 users liked answer #3dislike answer #30
Prateek shrivastava profile pic
Prateek shrivastava

According to docs of ts-jest you should set globals.tsConfig, but it must be globals.tsconfig. For example:

globals: {
    'ts-jest': {
      // ts-jest configuration goes here
      // https://huafu.github.io/ts-jest/user/config/#ts-jest-options
      // specify tsconfig.json to be used by ts-jest
      tsconfig: '<rootDir>/test/tsconfig.test.json',
    },
  },

With tsconfig in works for me, with tsConfig no.

Source: https://dev.to/ushakovmaksim/comment/1bc8j

0 users liked answer #4dislike answer #40
Vadym Berkut profile pic
Vadym Berkut

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