functional-chaining

Module that modifies prototypes of Array, String, Number and Object with useful functions.

How to use

npm i --save functional-chaining

import fc from 'functional-chaining';

fc.init()

or

const fc = require('functional-chaining');

fc.init()

Arrays

Includes the following functions for arrays:

Array._last

returns the last element from the array

[0, 1, 2, 3, 4]._last // 4

Array._head

returns the first element from the array

[0, 1, 2, 3, 4]._head // 0

Array._tail

returns the array except the first element

[0, 1, 2, 3, 4]._tail // [1, 2, 3, 4]

Array._distinct

returns the array with only unique values

[0, 0, 1, 0, 3, 3]._distinct // [0, 1, 3]

Array._count

Counts the elements which satisfy a function

[0, 1, 2, 3, 4]._count(v => v > 2) // 2

Array._take

Takes the first n elements of the array

[0, 1, 2, 3, 4]._take(3) // [0, 1, 2]

Array._drop

Takes all but the first n elements of the array

[0, 1, 2, 3, 4]._drop(3) // [3, 4]

Array._toSet

creates a set from the array

[0, 1, 2, 3, 4].toSet // [3, 4]

Strings

The following array properties are also defined for strings, with the same functionalities:

• String._last
• String._head
• String._tail
• String._take
• String._drop

Numbers

Number.isNaN

Equivalent of isNaN(number)

Objects

Object._forEach

Performs a function for each key-value pair

const obj = {a: 1, b: 2, c: 3};
obj._forEach((key, value) => {
  console.log(`${value}${key}`)
})
// Logs 1a, 2b and 3c

Object._forEachValue

Same as ._forEach but only takes the value as the callback function parameter

const obj = {a: 1, b: 2, c: 3};
obj._forEachValue(value => {
  console.log(value)
})
// Logs 1, 2 and 3

Object._map

Returns a new object mapped with a function

const obj = {a: 1, b: 2, c: 3};
obj._map((key, value) => {
  return value * 2
})
// {a: 2, b: 4, c: 6}

Object._mapValues

Same as ._map but only takes the value as the callback function parameter

const obj = {a: 1, b: 2, c: 3};
obj._mapValues(value => {
  return value * 2
})
// {a: 2, b: 4, c: 6}