Jest encountered an unexpected token with custom angular library

Question

I am trying to import my custom angular library from node_modules to my unit test, but I am getting this 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:

    C:\Users\user\Desktop\app\node_modules\@my-namespace\custom-lib\index.d.ts:5
    export * from './public-api';
    ^^^^^^
    
    SyntaxError: Unexpected token 'export'
    
      14 | import { NoopAnimationsModule } from '@angular/platform-browser/animations';
    > 16 | import { CustomPipe } from "@my-namespace\custom-lib";

This is the structure of my custom angular library in node_modules (main defined in package.json is "index.d.ts")

|--@my-namespace
   |--custom-lib
      |--esm2020
      |--fesm2015
      |--fesm2020
      |--lib
      |--index.d.ts
      |--public-api.d.ts
      |--package.json

This is my jest config:

import type { Config } from 'jest';

const config: Config = {
  preset: 'jest-preset-angular',
  setupFilesAfterEnv: ['<rootDir>/setup-jest.ts'],
  testPathIgnorePatterns: ['<rootDir>/node_modules/', '<rootDir>/dist/'],
  coveragePathIgnorePatterns: ['<rootDir>/src/app/modules/core/swagger-api'],
  moduleNameMapper: {
    '^@environments/(.*)': '<rootDir>/src/environments/$1',
    '^@app/(.*)': '<rootDir>/src/app/$1'
  },
  testMatch: [
    '**/__tests__/**/!(DISABLED.)*.[jt]s?(x)',
    '**/!(DISABLED.)?(*.)+(spec|test).[tj]s?(x)'
  ],
  globals: {
    'ts-jest': {
      tsconfig: '<rootDir>/tsconfig.spec.json',
      stringifyContentPathRegex: '\\.html$'
    }
  }
};

export default config;

And my tsconfig.spec.json:

{
  "extends": "./tsconfig.json",
  "compilerOptions": {
    "outDir": "./out-tsc/spec",
    "types": ["jest", "node"]
  },
  "files": ["src/polyfills.ts"],
  "include": ["src/**/*.spec.ts", "src/**/*.d.ts"]
}

I am using jest 28.1.3 wih jest-preset-angular 12.2.3. I have tried adding my library to transformIgnorePatterns but it didn't work. The structure of my library look almost identical to @ngx-translate, which seems to work with jest, unlike my library.

I am running out of ideas, any ideas how to solve this would be really helpful!

Jest encountered an unexpected token with custom angular library

0 Answers0