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 @m3.code/lotide

Require it:

const _ = require('@m3.code/lotide');

Call it:

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

Documentation

The following functions are currently implemented:

• assertArraysEqual(arr1, arr2): compares 2 arrays to see if they're equal and makes an assertion with results.

• assertEqual(actual, expected): implementation of our assert, comparing 2 values and see if they're equal

• assertObjectsEqual(actualObj, expectedObj): compares 2 objects to see if they're equal and makes an assertion with results.

• head(arr): Returns the 1st element of an array

• tail(arr): Returns the array without its head, all the following elements after the first one.

• middle(arr): Returns an array of the middle elements of the array, or the 2 middle elements of an array with an even number size length

• countLetters(sentence): Returns an object with Character key and count value pairs, describing a detailed count of characters inside the sentence.

  Example:

  countLetters('hello') => {h: 1, e: 1, l: 2, o:1}

• countOnly(allItems, itemsToCount): from an allItems object, we will count how many times the keys in itemToCount exist in this former object.

  Example:

  countOnly([
  "Karl",
  "Salima",
  "Agouhanna",
  "Fang",
  "Kavith",
  "Jason",
  "Salima",
  "Fang",
  "Joe"
  ], {Jason: true}) => 1

• eqArrays(arr1, arr2): compare 2 arrays and returns true if they're equal.

• eqObjects(obj1, obj2): compare 2 objects and returns true if they're equal.

• findKey(obj, callback): given an object, will return the key whose value meets the condition set in the callbback function.

  Example:

  findKey({
    "Blue Hill": { stars: 1 },
    "Akaleri": { stars: 3 },
    "noma": { stars: 2 },
    "elBulli": { stars: 3 },
    "Ora": { stars: 2 },
    "Akelarre": { stars: 3 }
  }, x => x.stars === 2); // => "noma"

• findKeyByValue(obj, value): given an object, will return the key whose value meets the value passed as argument

  Example:

  findKeyByValue({
    // eslint-disable-next-line camelcase
    sci_fi: "The Expanse",
    comedy: "Brooklyn Nine-Nine",
    drama: "The Wire"
  }, "The Wire") => drama

• flatten(arr): will "flatten" an array, making it unidimensional if there are nested arrays inside.

• letterPositions(sentence): will return an object with the characters as key and their index positions as array of numbers as values.

  Example:

  letterPositions('hello') => {h: [0], e:[1], l: [2,3], o: [4]}

• map(arr, callback): our implementation of the Array.map method. Takes an array and returns a new array given the oprations of the callback function.

• takeUntil(arr, callback): will return a new array from the elements of the passed arr until the condition set in callback is met (true).

  Example:

  takeUntil([1, 2, 5, 7, 2, -1, 2, 4, 5], x => x < 0) => [1, 2, 5, 7, 2]

• without(source, toRemove): returns a new array from the source from which we want to remove the elements present in the 2nd array toRemove.

  Example:

  without([1, 2, 3], [1]) => [2,3]