kobako-maybe v1.2.2

Maybe

Yet another Maybe type written by vanilla.js

Inspired by Haskell's Maybe type

Can be used in browser,node and requireJs

Installation

On browser or requireJs, just copy the src/maybe.js to desired path then use like this

<script src="/yourpath/maybe.js"></script>
<script>
  // Lib export 'M' to global
  console.log(M.or(M.just('Hello kobako-maybe'),'Oh no'))
</script>

By npm

$ npm install kobako-maybe

Usage

Import the lib:

const M = require('kobako-maybe')

Use the just of nothing function to create a Maybe type from a value

const value = M.just(1)

M.isJust(value) //true
M.isNothing(value) //false

const val2 = M.nothing()

M.isJust(val2) //false
M.isNothing(val2) //true

Use map to lift a function: you can use a traditional function on a Maybe value

const value = M.just(1)
const nothing = M.nothing()

M.map(x => x+1, value) //Just 2
M.map(x => x+1, nothing) //Nothing

Use or to unwrap value from Maybe

M.or(M.just(1),-1) //1
M.or(M.nothing(),-1) //-1