Ts-jest

API

testHelpers

• source: https://kulshekhar.github.io/ts-jest/user/test-helpers

// foo.spec.ts
import { mocked } from 'ts-jest/utils'
import { foo } from './foo'
jest.mock('./foo')

// here the whole foo var is mocked deeply
const mockedFoo = mocked(foo, true)

test('deep', () => {
  // there will be no TS error here, and you'll have completion in modern IDEs
  mockedFoo.a.b.c.hello('me')
  // same here
  expect(mockedFoo.a.b.c.hello.mock.calls).toHaveLength(1)
})

test('direct', () => {
  foo.name()
  // here only foo.name is mocked (or its methods if it's an object)
  expect(mocked(foo.name).mock.calls).toHaveLength(1)
})

Cook

preset

// OR package.json
{
  // [...]
  "jest": {
    "globals": {
      "ts-jest": {
        // ts-jest configuration goes here
      }
    }
  }
}

Custom tsconfig

module.exports = {
  // [...]
  globals: {
    'ts-jest': {
      tsConfig: 'tsconfig.test.json'
    }
  }
};

Inline Options

module.exports = {
  // [...]
  globals: {
    'ts-jest': {
      tsConfig: {
        importHelpers: true
      }
    }
  }
};

Babel7 vs typescript

• url: https://kulshekhar.github.io/ts-jest/user/babel7-or-ts

• babel

  • no typechecking
  • no namespacing
  • no const enum
  • no declaration merging
  • no legacy import/export

import lib = require('lib')

- no caret type casting with jsx