@zhabskyi/lotide v1.0.1

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 @zhabskyi/lotide

Require it:

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

Call it:

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

Documentation

The following functions are currently implemented:

• middle:

Function should return an array with only the middle element(s) of the provided array. This means that the length of the returned elements could vary.

• For arrays with one or two elements, there is no middle. Return an empty array.

  middle([1]) // => []
  middle([1, 2]) // => []

• For arrays with odd number of elements, an array containing a single middle element should be returned.

  middle([1, 2, 3]) // => [2]
  middle([1, 2, 3, 4, 5]) // => [3]

• For arrays with an even number of elements, an array containing the two elements in the middle should be returned

  middle([1, 2, 3, 4]) // => [2, 3]
  middle([1, 2, 3, 4, 5, 6]) // => [3, 4]

Expected Output 1, 2, 5, 7, 2 ;

• withOut

Function return a subset of a given array, removing unwanted elements.

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

• flatten

Function take in an array of arrays and return a "flattened" version of the array.

flatten([1, 2, [3, 4], 5, [6]]) // => [1, 2, 3, 4, 5, 6]

• countOnly

Function return an object containing counts of everything that the input object listed.

const firstNames = [
  "Karl",
  "Salima",
  "Agouhanna",
  "Fang",
  "Kavith",
  "Jason",
  "Salima",
  "Fang",
  "Joe"
];

const result = countOnly(firstNames, { "Jason": true, "Karima": true, "Fang": true });
result = { Fang: 2, Jason: 1 };

• letterPosition

Function return all the indices (zero-based positions) in the string where each character is found.

letterPositions("lighthouse in the house"); // =>
{ l: [ 0 ],
  i: [ 1, 11 ],
  g: [ 2 ],
  h: [ 3, 5, 15, 18 ],
  t: [ 4, 14 ],
  o: [ 6, 19 ],
  u: [ 7, 20 ],
  s: [ 8, 21 ],
  e: [ 9, 16, 22 ],
  n: [ 12 ] }

• findKeyByValue

Function takes in an object and a value. It should scan the object and return the first key which contains the given value. If no key with that given value is found, then it should return undefined.

const bestTVShowsByGenre = {
  sciFi: "The Expanse",
  comedy: "Brooklyn Nine-Nine",
  drama:  "The Wire"
};

findKeyByValue(bestTVShowsByGenre, "The Wire"); // => "drama"
findKeyByValue(bestTVShowsByGenre, "That '70s Show"); // => undefined

• eqObjects

Function take in two objects and returns true or false, based on a perfect match.

• countLetters

Function return an object where each unique character encountered is a property of the object and the value for that property/key should be the number of occurrences for that character.

countLetters("lighthouse in the house");
{
  l: 1,
  i: 2,
  g: 1,
  h: 4,
  t: 2,
  o: 2,
  u: 2,
  s: 2,
  e: 3,
  n: 1,
}

• takeUtil:

Function keep collecting items from a provided array until the callback provided returns a truthy value.

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

Expected Output 1, 2, 5, 7, 2 ;

• findKey:

Function takes in an object and a callback. It should scan the object and return the first key for which the callback returns a truthy value. If no key is found, then it should return undefined.

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

Expected Output "noma".