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---
id: mock-es6-class
title: Mock ES6 class
---
TypeScript is transpiling your ts file and your module is likely being imported using ES2015s import.
`const soundPlayer = require('./sound-player')`. Therefore creating an instance of the class that was exported as
a default will look like this: `new soundPlayer.default()`. However if you are mocking the class as suggested by the documentation.
```js tab
jest.mock('./sound-player', () => {
return jest.fn().mockImplementation(() => {
return { playSoundFile: mockPlaySoundFile }
})
})
```
```ts tab
jest.mock('./sound-player', () => {
return jest.fn().mockImplementation(() => {
return { playSoundFile: mockPlaySoundFile }
})
})
```
You will get the error
```
TypeError: sound_player_1.default is not a constructor
```
because `soundPlayer.default` does not point to a function. Your mock has to return an object which has a property default
that points to a function.
```js tab
jest.mock('./sound-player', () => {
return {
default: jest.fn().mockImplementation(() => {
return {
playSoundFile: mockPlaySoundFile,
}
}),
}
})
```
```ts tab
jest.mock('./sound-player', () => {
return {
default: jest.fn().mockImplementation(() => {
return {
playSoundFile: mockPlaySoundFile,
}
}),
}
})
```
For named imports, like `import { OAuth2 } from './oauth'`, replace `default` with imported module name, `OAuth2` in this example:
```js tab
jest.mock('./oauth', () => {
return {
OAuth2: ... // mock here
}
})
```
```ts tab
jest.mock('./oauth', () => {
return {
OAuth2: ... // mock here
}
})
```
|
