Functional Implementations of Mutative Array Methods

A set of simple utilities for working with Arrays without modifying them.

Installation

Install from npm via your package manager of choice;

npm install fimam

yarn add fimam

API

The intent behind this library was to create utilities that take the familiar verbs from native array methods but perform the work in a way that adheres to the principles of functional programming.

fpop

Designed to mimic the pop native array method, fpop takes an array and returns a copy, omitting the element with the highest index.

import { fpop } from 'fimam';

const startingArray = [1, 2, 3, 4, 5];
const newArray = fpop(startingArray);

console.log(newArray) => [1, 2, 3, 4];

fpush

Designed to mimic the push native array method, fpush takes an array and returns a copy, appending the remaining arguments to it.

import { fpush } from 'fimam';

const startingArray = [1, 2, 3];
const newArray = fpush(startingArray, 4, 5, 6);

console.log(newArray) => [1, 2, 3, 4, 5, 6];

If the element to be added is another array, fpush will return a copy with the two concatenated in order.

import { fpush } from 'fimam';

const startingArray = [1, 2, 3];
const newArray = fpush(startingArray, [4, 5, 6]);

console.log(newArray) => [1, 2, 3, 4, 5, 6];

fshift

Designed to mimic the shift native array method, fshift takes an array and returns a copy, omitting the element with the lowest index.

import { fshift } from 'fimam';

const startingArray = [1, 2, 3, 4, 5];
const newArray = fshift(startingArray);

console.log(newArray) => [2, 3, 4, 5];

fsplice

Designed to mimic the splice native array method, fsplice takes an array and returns a copy, having removed the passed number of elements starting at the passed index.

import { fsplice } from 'fimam';

const startingArray = [1, 2, 3, 4, 5];
const newArray = fsplice(startingArray, 1, 2);

console.log(newArray) => [1, 2, 5];

If additional elements are passed, they will be added to the modified array, starting at the passed index.

import { fsplice } from 'fimam';

const startingArray = [1, 2, 3, 4, 5];
const newArray = fsplice(startingArray, 1, 2, 'three', 'four');

console.log(newArray) => [1, 2, 'three', 'four', 5];

funshift

Designed to mimic the unshift native array method, funshift takes an array and returns a copy, prepending the passed elements to it.

import { funshift } from 'fimam';
const startingArray = [1, 2, 3];
const newArray = funshift(startingArray, 4, 5)

console.log(newArray) => [4, 5, 1, 2, 3];

Support

Please file an issue if there are any gaps or mistakes.