Lotide

A mini clone of the Lodash library.

Purpose

BEWARE: This library was published for learning purposes. It is not intended for use in production-grade software.

This project was created and published by me as part of my learnings at Lighthouse Labs.

Usage

Install it:

npm install @souredoutlook/lotide

Require it:

const _ = require('@souredoutlook/lotide');

Call it:

const results = _.tail([1, 2, 3]) // => [2, 3]

Documentation

The following functions are currently implemented:

• assertArraysEqual(array1,array2)): a simple assertion tool for comparing shallow arrays. Logs passing and failing results.
• assertEqual(value1,value2): a simple assertion tool for numbers, "strings", boolean, undefined and null. Logs passing and failing results.
• assertObjectEquals({a:1, b:2},{b:2, a:1}): a simple assertion tool for shallow Objects, supports shallow arrays as values. Logs passing and failing results.
• countLetters("string"): given a string, returns an object containing key:value pairs that reflect letters, and their frequency of appearance in a string. Example: {s: 1, t: 1, ...etc} Key's are lowerCase. Count is based on /[a-zA-Z]/.
• countOnly([x,y], {x: true, y: false}): returns an object containing key:value pairs that reflect the frequency which a key appears in a given array (example: {x: 1}) if some variation of {'key':true} is passed as an argument.
• eqArrays(array1, array2): returns true if arrays of identical lengths are found to contain identical elements in the same indices.
• eqObjects({a: 1, b: [2]}{b: [2], a: 1}: returns true if objects with indentical keys contain identical values. Supports shallow arrays as values.
• findKey({"noma": {stars: 2}, "elBulli": {stars: 3}, x => x === 2): returns the key of an object when the callback argument returns true. Example: noma.
• findKeyByValue({a:1, b:2, c:'three'}, 'three'): returns the first key in an object that is paired with a given value. Example: 'c'.
• flatten([1,[2,3],4]): will flatten an array with elements that contain shallow arrays. IS NOT RECURSIVE. Example: [1,2,3,4]
• head([1,2,3]): returns the 0th index of an array. Example: [1]
• letterPositions("abba"): given a string, returns an object with key:value pairs with keys that correspond to letters in a string, and values that are arrays containing the string indices of the letter as elements. Example: {a: [0,3], b:[1,2]}. Key's are lowerCase. Count is based on /[a-zA-Z]/.
• map([1,2,3], x => x * 2): returns a copy of an array containing elements where the callback function evaluates to true. Can result in a new array of differing length if the callback function contains a return inside a conitional (this is by design).
• middle([1,2,3]): returns the middle element for arrays of odd length. Or, returns the middle two elements for arrays of even length.
• tail([1,2,3]): returns all but the 0th index of an array.
• takeUntil([1,2,3], x => x > 2): iterates over an array and returns it's indices in order as an array until a callback argument evaluates to true. Example: [1,2].
• without([1,2,3], ['one','two',3]): given two arrays, will return a copy of the first array without any elements that are found to be in the second array. Example: [1,2,].