https://github.com/dgreene1/typesafejestspy

DEPRECATED-- Jest now includes types. Former description: Helps you write faster spies by automatically inferring the real implementation's type signature
https://github.com/dgreene1/typesafejestspy

jest spies typescript

Last synced: 4 months ago
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DEPRECATED-- Jest now includes types. Former description: Helps you write faster spies by automatically inferring the real implementation's type signature

• Host: GitHub
• URL: https://github.com/dgreene1/typesafejestspy
• Owner: dgreene1
• License: gpl-3.0
• Created: 2018-12-14T17:57:21.000Z (about 6 years ago)
• Default Branch: master
• Last Pushed: 2020-10-27T20:43:03.000Z (over 4 years ago)
• Last Synced: 2024-10-04T21:38:09.138Z (4 months ago)
• Topics: jest, spies, typescript
• Language: TypeScript
• Homepage:
• Size: 22.5 KB
• Stars: 7
• Watchers: 3
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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README

        
# DEPRECATED: Yay! Jest has been [rewritten in TypeScript](https://github.com/facebook/jest/commit/be2703c103b63850a7a8fc244edf8e3c7798a9f3), so you no longer need to use this library! Enjoy the beautiful types of Jest.

## typeSafeJestSpy

A _very thin_ layer that helps you write faster spies by automatically inferring the real implementation's type signature

### Why would you use this?

  * Have you ever made a spy for entirely the wrong function?

  * Have you ever returned bad data from a spy by accident?

    * i.e. you knew that the method you were replacing was supposed to return a string... but you accidentally returned a number?

Who would want false-positive unit tests? Accidental mistakes with spies are a thing of the past with typeSafeJestSpy! :)

### How do you use this?

  * Please see the unit tests in the test folder for usage examples

Simply send your Jest spy into a function of this library and then the following Jest spy functions will require you to return the correct type:

  * `mockImplementation`

  * `mockImplementationOnce`

  * `mockResolvedValue`

  * `mockResolvedValueOnce`

### Caveats

Please see the version of Jest in my package.json to see what this micro-library thinks is the way that Jest behaves. If your version of Jest is wildly different, then

  * you might get irregular behavior.

  * you might find that Jest has introduced a type-safe version itself, in which case this library would no longer be required