Unable to run jest with typescript - "Cannot find module 'typescript'"

Question

I'm trying to run jest with typescript, but I'm getting following error. The project runs fine in webpack and with ts-node. For some reason I can't get it to work with jest.

FAIL  src/__tests__/classes/Utils.spec.ts
● Test suite failed to run

Cannot find module 'typescript'

Require stack:
- /Users/myuser/repos/project/node_modules/ts-jest/dist/config/config-set.js
- /Users/myuser/repos/project/node_modules/ts-jest/dist/ts-jest-transformer.js
- /Users/myuser/repos/project/node_modules/ts-jest/dist/index.js
- /Users/myuser/repos/project/node_modules/@jest/transform/build/ScriptTransformer.js
- /Users/myuser/repos/project/node_modules/@jest/transform/build/index.js
- /Users/myuser/repos/project/node_modules/jest-runtime/build/index.js
- /Users/myuser/repos/project/node_modules/@jest/core/build/cli/index.js
- /Users/myuser/repos/project/node_modules/@jest/core/build/jest.js
- /Users/myuser/repos/project/node_modules/jest/node_modules/jest-cli/build/cli/index.js
- /Users/myuser/repos/project/node_modules/jest/node_modules/jest-cli/bin/jest.js
- /Users/myuser/repos/project/node_modules/jest/bin/jest.js
- /usr/local/lib/node_modules/jest/node_modules/import-local/index.js
- /usr/local/lib/node_modules/jest/bin/jest.js

jest.config.js

This is the configuration. I've tried many variations on the roots property and moduleNameMapper, but the error message is exactly the same no matter what I change in the config.

module.exports = {
  preset: 'ts-jest',
  testEnvironment: 'node',
  roots: ['<rootDir>/src'],
  transform: {
    '^.+\\.tsx?$': 'ts-jest',
  },
  testRegex: '(/__tests__/.*|(\\.|/)(test|spec))\\.tsx?$',
  moduleFileExtensions: ['ts', 'tsx', 'js', 'jsx', 'json', 'node'],
  moduleDirectories: ['node_modules', 'src'],
  moduleNameMapper: {
    '^src/(.*)$': '<rootDir>/src/$1',
  }
};

tsconfig.json

{
    "compilerOptions": {
        "baseUrl": "./",
        "paths": {
            "src/*": ["src/*"],
            "tests/*": ["__tests__/*"]
        },
        "target": "es6",
        "module": "commonjs",
        "esModuleInterop": true,
        "moduleResolution": "node",
        "emitDecoratorMetadata": true,
        "experimentalDecorators": true,
        "sourceMap": true,
        "inlineSourceMap": false,
        "outDir": "dist",
        "lib": ["es6", "dom", "esnext", "esnext.asynciterable"],
        "typeRoots": ["node_modules/@types", "src/typings"]
    },
    "awesomeTypescriptLoaderOptions": {
        "useBabel": true,
        "useCache": true,
        "useTranspileModule": true
    },
    "include": ["src/**/*.ts"],
    "exclude": ["./node_modules/*"]
}

Utils.spec.js

import { Utils } from 'src/utils/classes/Utils';

test('Generates a 6 digit number'), () => {
    expect(Utils.randomNumberGenerator(6).toHaveLength(6))
});

Utils.ts

export class Utils {
    public static randomNumberGenerator(length: number): number {
        const baseNumber: number = Number(1 + '0'.repeat(length - 1));
        const randomMultiplier: number = Math.floor(Math.random() * Number('9' + '0'.repeat(length - 1)));
        const randomToken: number = baseNumber + randomMultiplier;
        return randomToken;
    }
}

It looks like you haven't installed typescript in your local deps? — tmhao2005
– tmhao2005, Commented Aug 21, 2020 at 10:01
@tmhao2005 "typescript": "^3.3.3333" can be located in packages.json. Ran an npm install typescript just in case and same problem. — Jørgen V
– Jørgen V, Commented Aug 21, 2020 at 10:16
Were you successful to install that kind of weird version? It’s supposed to be like 3.9.7 instead — tmhao2005
– tmhao2005, Commented Aug 21, 2020 at 10:19
@tmhao2005 Yes, but since you pointed it out I tried to upgrade by running npm i typescript@latest which installed typescript 4.0.2 for me. Still same issue. — Jørgen V
– Jørgen V, Commented Aug 21, 2020 at 10:24
Looks like you installed your jest stuff globally which ends up the issue so try install locally and try again — tmhao2005
– tmhao2005, Commented Aug 21, 2020 at 10:43

Jørgen V · Accepted Answer · 2020-08-21 10:53:38Z

9

@tmhao kindly helped me with this issue.

Problem was that ts-jest was not installed. A bit unclear error message.

answered Aug 21, 2020 at 10:53

Jørgen V

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2 Comments

Dmitrii Rogozin Over a year ago

Thank you sir :D I do agree the error message is not the best

pythlang Over a year ago

Wow, thank you! The following error clued me in node_modules/jest-cli/build/cli/index.js:161 if (error?.stack) { ^ SyntaxError: Unexpected token .

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