https://github.com/mudssrali/cond-construct

Elixir's cond construct implementation for Javascript and Typescript
https://github.com/mudssrali/cond-construct

cond control-flow elixir-cond elixir-lang javascript typescript

Last synced: about 1 month ago
JSON representation

Elixir's cond construct implementation for Javascript and Typescript

• Host: GitHub
• URL: https://github.com/mudssrali/cond-construct
• Owner: mudssrali
• Created: 2020-05-01T23:30:43.000Z (over 4 years ago)
• Default Branch: master
• Last Pushed: 2022-09-28T19:03:09.000Z (about 2 years ago)
• Last Synced: 2024-09-14T16:24:02.136Z (2 months ago)
• Topics: cond, control-flow, elixir-cond, elixir-lang, javascript, typescript
• Language: TypeScript
• Homepage:
• Size: 124 KB
• Stars: 2
• Watchers: 2
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.md

Awesome Lists containing this project

README

        
# cond-construct

Inspired by [Elixir's `cond`](https://elixir-lang.org/getting-started/case-cond-and-if.html#cond) this is a simpler alternative to [lodash's `_.cond`](https://lodash.com/docs/4.17.15#cond)

[![CI status](https://circleci.com/gh/mudssrali/cond-construct.svg?style=shield)](LINK)

[![JavaScript Style Guide](https://img.shields.io/badge/code_style-standard-brightgreen.svg)](https://standardjs.com)

[![tested with jest](https://img.shields.io/badge/tested_with-jest-99424f.svg)](https://github.com/facebook/jest)



  



## Install

Install with npm or yarn via

```

yarn add cond-construct

```

or

```

npm i cond-construct

```

## API

```ts

type Cond = (

  pairs: Array<[boolean, unknown | (() => unknown)]>,

  options?: { strict: boolean }

) => unknown

```

## Usage

```js

import cond from 'cond-construct'

const value = cond([

  [false, 'false'],

  [true, 'true'],

  [true, 'true but too late']

])

// value === 'true'

```

You can disable strict checking by passing options as the second argument:

```js

import cond from 'cond-construct'

const value = cond(

  [

    [false, 'false'],

    [1, 'truthy'],

    [true, 'true but also too late']

  ],

  { strict: false }

)

// value === 'truthy'

```

Also works nicely with React components as you can have the values lazily evaluated by wrapping it in a function:

```jsx

import cond from 'cond-construct'

const Component = ({ hasErrors, isNew, isLoading }) => (

  <>

    {cond([

      [isLoading, () => ],

      [isNew, () => ],

      [hasErrors, () => ]

    ])}

  >

)

```

### Next

- [] Handle multiple method executions

- [] Add more option for falsy value

### Note

As all predicates have to be evaluated before the right branch can be chosen, it can have a negative performance impact if you rely on heavy computations here. It's best have simple booleans and resort to `_.cond` for complex use cases.