CODEWITHSUNDEEP
typescriptjestjs
Alex Seifert
Alex Seifert

Reputation: 163

Jest/Typescript: Importing a File Breaks Import in Another File

I'm having a strange issue with my unit tests and Jest that I have no idea how to solve. When I import a file in file2.ts, the import of the same file in file1.ts becomes undefined. The application builds and runs, but the unit tests no longer work and throw the following error in file1.ts:

TypeError: Cannot read property 'getModel' of undefined

This is the code:

file1.ts

import users from '../users';

const model = users.getModel();

...

file2.ts

import users from '../../users';

const model = users.getModel();

...

users.ts

export class User {
  getModel() {
    ...
  }
}

export default new User();

The unit test for file2.ts throws the error above for file1.ts even though I am only running the unit test for file2.ts specifically.

If I comment out const model = users.getModel(); in file2.ts, then the error isn't thrown.

Here are my tsconfig.json and my jest.config.js files:

tsconfig.json

{
  "compilerOptions": {
    "module": "commonjs",
    "moduleResolution": "node",
    "pretty": true,
    "sourceMap": false,
    "target": "es6",
    "resolveJsonModule": true,
    "esModuleInterop": true,
    "allowJs": true,
    "outDir": "./dist",
    "baseUrl": "./src"
  },
  "include": [
    "src/**/*.ts"
  ],
  "exclude": [
    "dist",
    "node_modules",
    "**/*.spec.ts"
  ]
}

jest.config.js

module.exports = {
  preset: 'ts-jest',
  testEnvironment: 'node',
  collectCoverage: true,
  coverageDirectory: './test-coverage'
};

Any ideas?

Upvotes: 0

Views: 2457

Answers (1)

Jed Richards
Jed Richards

Reputation: 12435

You might have a circular dependency, but I can't tell from the truncated example code you posted. But circular deps can cause imports to show up as undefined due to race conditions. You can use the eslint-plugin-import/no-cycle rule to check for circular deps, and then refactor them out of your code base.

Upvotes: 0

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