https://github.com/freckle/exhaustive-js

Provides a helper function for checking exhaustiveness.
https://github.com/freckle/exhaustive-js

ghvm-managed

Last synced: about 1 year ago
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Provides a helper function for checking exhaustiveness.

• Host: GitHub
• URL: https://github.com/freckle/exhaustive-js
• Owner: freckle
• License: mit
• Created: 2022-04-08T15:53:25.000Z (about 4 years ago)
• Default Branch: main
• Last Pushed: 2025-04-05T02:23:41.000Z (about 1 year ago)
• Last Synced: 2025-05-07T09:51:51.557Z (about 1 year ago)
• Topics: ghvm-managed
• Language: TypeScript
• Homepage:
• Size: 45.9 KB
• Stars: 0
• Watchers: 12
• Forks: 0
• Open Issues: 3
• Metadata Files:
  • Readme: README.md
  • License: LICENSE
  • Codeowners: .github/CODEOWNERS

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README

          
# @freckle/exhaustive-js

Provides a helper function for checking exhaustiveness. Exhaustiveness checking is a feature of a language where the type checker guarantees that all cases were covered.

## Usage

```js

import {exhaustive} from '@freckle/exhaustive-js'

type Status = 'success' | 'failure'

function getStatusMessage(status: Status): string {

  switch (status) {

    case 'success':

      return 'The operation completed successfully.'

    case 'failure':

      return 'The operation failed.'

    default:

      return exhaustive(status)

  }

}

```

Usage in a reducer where returning the state itself in the default case is a common pattern:

```js

import {exhaustiveReducer} from '@freckle/exhaustive-js'

type TodoState = {...}

type TodoAction = {type: 'todoAdded', ...} | {type: 'todoToggled', ...}

const defaultTodoState = {...}

function todoReducer(

  state: TodoState = defaultTodoState,

  action: TodoAction

): TodoState {

  switch (action.type) {

    case 'todoAdded':

      return {...}

    case 'todoToggled':

      return {...}

    default:

      return exhaustiveReducer(action.type, state)

  }

}

```