functional

Functional JavaScript

Installation

In a browser e.g.

<script type="module">
import { head } from './array.mjs'
// Get first element
const first = head(['foo', 'bar'])
console.log(first)
// => foo
</script>

In Node.js:

The --experimental-modules flag can be used to enable features for loading ESM modules.

$ npm init -y
$ npm i daliborgogic/functional
$ touch index.mjs
// index.mjs
import { last } from './node_modules/functional/array'
// Get last element
const rear = last(['foo', 'bar'])
console.log(rear)
$ node --experimental-modules index.mjs
> bar

Array

combine(array) Combine multiple arrays into one array.

compact(array) Returns a copy of the array with all falsy values removed.

contains(array, value) Returns true if the value is present in the array.

difference(array, others) Similar to without, but returns the values from array that are not present in the other arrays.

head(array) Gets the first element of array.

initial(array) Returns everything but the last entry of the array.

intersection(arrays) Computes the list of values that are the intersection of all the arrays. Each value in the result is present in each of the arrays.

last(array) Returns the last element of an array.

sortedIndex(array, value) Determine the index at which the value should be inserted into the array in order to maintain the array’s sorted order.

tail(array) Returns everything but the first entry of the array.

toArray(arrayLike) Returns a real Array. Useful for transmuting the arguments object.

union(arrays) Computes the union of the passed-in arrays: the list of unique items, in order, that are present in one or more of the arrays.

unique(array) Produces a duplicate-free version of the array.

without(array, values) Returns a copy of the array with all instances of the values removed.

Object

getValues(object) Returns an array with the object’s values.

merge(objects) Combine multiple objects into a new object.

toMap(object)Convert an Object to a Map.

Math

min(array) Returns the minimum value in the array.

max(array) Returns the maximum value in the array.

sum(array) Returns the sum of all values in the array.

product(array) Returns the product of all values in the array.

Decorators

not(function) Creates a new function returning the opposite of the function provided as its argument.

maybe(function) Returns a new function that won’t execute if not enough arguments are provided.

once(function) Returns a new function that won’t execute more than once.

curry(function) Curries a function.

pipeline(functions) Returns the composition of multiple functions from left to right.