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 @jcarloflores/lotide

Require it:

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

Call it:

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

Documentation

The following functions are currently implemented:

• countLetters(sentence): Returns an object with key-value pairs with a total count for each letter.

  Since

  • 1.0.1

  Arguments

  • sentence (String): The string to process.

  Returns

  • (Object): Returns an object with key-value pair summary per letter.

  Example

  _.countLetters('Hello World');
  // => { h: 1, 
  //      e: 1, 
  //      l: 3, 
  //      o: 2, 
  //      w: 1, 
  //      r: 1, 
  //      d: 1 }

• countOnly(allItems, itemsToCount): Returns an object with key-value pair count based on itemsToCount object of matching key and boolean value of true.

  Since

  • 1.0.1

  Arguments

  • allItems (Array): Array of strings to process.
  • itemsToCount (Object): Object with keys of what to count paired with boolean values.

  Returns

  • (Object): Returns an object with key-value pair count for each matching key with true values.

  Example

  const firstNames = [
    "Hello",
    "World",
    "Foo",
    "Bar",
    "Code",
    "World",
    "Bar",
  ];
  
  _.countOnly(firstNames, { World: true, Blaster: true, Bar: false});
  // => { World: 2 }

• eqArrays(array1, array2): Returns a boolean value depending whether or not both arrays are strictly equal to each other.

  Since

  • 1.0.1

  Arguments

  • array1 (Array): First array for comparison.
  • array2 (Array): Second array for comparison.

  Returns

  • (Boolean): Returns an boolean value (true or false) if both arrays are strictly equal.

  Example

  const array1 = [1, [2], 3];
  const array2 = [1, [2], 3];
  
  _.eqArrays(array1, array2);
  // => true

• eqObjects(object1, object2): Returns a boolean value depending whether or not both objects are strictly equal to each other.

  Since

  • 1.0.1

  Arguments

  • object1 (Object): First object for comparison.
  • object2 (Object): Second object for comparison.

  Returns

  • (Boolean): Returns an boolean value (true or false) if both objects are strictly equal.

  Example

  const object1 = {a: 1, b: {c: 2}, d: 2};
  const object2 = {a: 1, d: 2, b: {c: 2}};
  
  _.eqObjects(object1, object2);
  // => true

• findKey(object, callback): Returns key of object if the value of the key is truthy when using with the callback.

  Since

  • 1.0.1

  Arguments

  • object (Object): The object to evaluate.
  • callback (Function): Callback function that takes in object[key] as argument.

  Returns

  • (Object): Returns first key with truthy callback(value).

  Example

  const toys = () => {
    "car":     { shelflife: 3},
    "ball":    { shelflife: 2},
    "doll":    { shelflife: 4),
    "device":  { shelflife: 2},
    "top":     { shelflife: 5},
  }
  
  _.findKey(toys, toy =>  toy.shelflife === 2);
  // => "ball"

• flatten(array): Returns an array without any nesting.

  Since

  • 1.0.1

  Arguments

  • array (Array): The array to evaluate.

  Returns

  • (Object): Returns flattened array.

  Example

  const array = [1, 2, [3, 4], 5, [6]];
  
  _.flatten(array);
  // => [1, 2, 3, 4, 5, 6]

• head(array): Returns the first item in the array.

  Since

  • 1.0.0

  Arguments

  • array (Array): The array to process.

  Returns

  • (Array): Returns the first element of array.

  Example

  _.head(['a', 'b', 'c']);
  // => 'a'
  
  _.head([1, 2, 3]);
  // => 1

• letterPositions(sentence): Returns an object with key-value pairs that correspond to the index locations of each letter from provided string.

  Since

  • 1.0.1

  Arguments

  • sentence (String): The string to evaluate.

  Returns

  • (Object): Returns object index locations of each letter in the sentence.

  Example

  const sentence = "hello";
  
  _.letterPositions(sentence);
    // => { h: [0], 
    //      e: [1], 
    //      l: [2, 3], 
    //      o: [4] }

• map(array, callback): Returns a new array with each value modified based on the callback.

  Since

  • 1.0.1

  Arguments

  • array (Array): The array to evaluate.
  • callback (Function): Callback function that modifies each object[key].

  Returns

  • (Object): Returns new array where each value has been modified by the callback function.

  Example

  const numbers = [1, 2, 3, 4, 5];
  _.map(numbers, n => n * 2);
  // => [2, 4, 6, 8, 10]

• middle(array): Returns the middle item of the first of the array.

  Since

  • 1.0.0

  Arguments

  • array (Array): The array to process.

  Returns

  • (Array): Returns the middle element of array. If the array length is even, it will return two elements.

  Example

  _.middle(['a', 'b', 'c']);
  // => 'b'
  
  _.middle([1, 2, 3, 4]);
  // => '[2, 3]

• tail(array): Returns every item in the array except the first item (head).

  Since

  • 1.0.0

  Arguments

  • array (Array): The array to process.

  Returns

  • (Array): Returns every item in an array except the first item.

  Example

  _.tail(['a', 'b', 'c']);
  // => ['b', 'c']
  
  _.tail([1, 2, 3, 4]);
  // => '[2, 3, 4]

• takeUntil(array, callback): Evaluates each element starting from the beginning until callback evaluates true.

  Since

  • 1.0.1

  Arguments

  • array (Array): The array to evaluate.
  • callback (Function): Callback function that evaluates each element.

  Returns

  • (Array): Returns new array with elements up till element satisfies callback condition.

  Example

  const array = [1, 2, 5, 7, 2, -1, 2, 4, 5];
  _.takeUntil(array, x => x < 0);
  // => [ 1, 2, 5, 7, 2 ]

• without(source, itemsToRemove): Evaluates each element in the array and removes elements that match itemsToRemove.

  Since

  • 1.0.1

  Arguments

  • source (Array): The array to evaluate.
  • itemsToRemove (Array): The array containing elements to compare for removal.

  Returns

  • (Array): Returns new array with elements that do not contain itemsToRemove.

  Example

  const array = [1, 2, 3];
  _.without(array, [1]);
  // => [2, 3]