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README.md

scala-like-option

Build Status

Option that covers all API functions from Scala Option monad in javascript for handling null in declarative way

install

npm install --save scala-like-option

usage

const optionFactory = require('scala-like-option')

var some = optionFactory.Some('some-content');
var transformation = optionFactory.map(content => 'other-content'); // == 'other-content'

var none = optionFactory.Option(null); // option from null == none
var none = optionFactory.None();
var some = optionFactory.Option('some-content'); // Some('some-content')
var some = some.getOrElse('other-content') // 'some-content'
var some = some.fold('empty', c => 'data') // returns 'data'

Api

getOrElse(elseObject)

Returns the item or the elseObject if None

Arguments:

  • elseObject: the object that returns of was None

get()

Returns the element or throws NoSuchElementException if was None

orElse(Else)

Returns current option if Some or the Else if None

Arguments:

  • Else: other option to return

orNull()

Returns the element or null if was None

isEmpty()

Return true if None and false if Some

isDefined()

Return false if None and true if Some

map(transformer)

Returns different option with the transformer predicate

Arguments:

  • transformer: function that gets the element and returns new object

fold(ifEmpty, applyNonEmpty)

Return value from supplied function, one for None and one For Some

Arguments:

  • ifEmpty: value returned from this function if is None
  • applyNonEmpty: value returned from this function if is Some

flatMap(transformer)

Returns different option for given transformer

Arguments:

  • transformer: function that gets the element and returns new option, it may be None

filter(predicate)

Returns the content if predicate returns true

Arguments:

  • predicate: function that gets the element and returns true/false

filterNot(predicate)

Returns the content if predicate returns false

Arguments:

  • predicate: function that gets the element and returns true/false

find(predicate)

Returns the content if predicate returns true

Arguments:

  • predicate: function that gets the element and returns true/false

forAll(predicate)

Returns true if give predicate on this element returns true, if None returns always true

Arguments:

  • predicate: function that gets the element and returns true/false

contains(containElement)

Returns true if the element is equal to give parameter, if none returns false

Arguments:

  • containElement: element to check equality

exists(predicate)

Checks if element exists for given predicate

Arguments:

  • predicate: function that return true/false and gets the element

forEach(executor)

Execute function with element, do nothing when None

Arguments:

  • executor: function that called with the element

toList()

Return array from option, if None it returns empty array

iterator()

Returns iterator from option, end iterator if none