Lodash library. Common overview

Why did I choose this topic

Why Lodash?

Lodash makes JavaScript easier by taking the hassle out of working with arrays, numbers, objects, strings, etc. Lodash’s modular methods are great for:

  • Iterating arrays, objects, & strings
  • Manipulating & testing values
  • Creating composite functions
To install this library:

1. You can insert tag script with lodash as source to your html file.

script-tag

2. Using npm.


							$ npm i -g npm
							$ npm i --save lodash

3. In Node.js.


							// Load the full build.
							var _ = require('lodash');
							// Load the core build.
							var _ = require('lodash/core');
							// Load the FP build for immutable auto-curried
							iteratee-first data-last methods.
							var fp = require('lodash/fp');

							// Load method categories.
							var array = require('lodash/array');
							var object = require('lodash/fp/object');

							// Cherry-pick methods for smaller
							browserify/rollup/webpack bundles.
							var at = require('lodash/at');
							var curryN = require('lodash/fp/curryN');

Chunk Method

Goal: create an array of elements split into groups the length of size.
My JS Implementation 

function myChunk(arr, size = 1) {
	const output = [];
	for (let i = 0; i < arr.length; i += size ){
		let arrayChunk = arr.slice(i, i + size);
		output.push(arrayChunk);
	}
	return output;
}

myChunk(['a', 'b', 'c', 'd', 'e', 'f'], 2);
//--> [ [ 'a', 'b' ], [ 'c', 'd' ], [ 'e', 'f' ] ]

myChunk(['a', 'b', 'c', 'd', 'e'], 3);
//--> [ [ 'a', 'b', 'c' ], [ 'd', 'e' ] ]
Lodash Method 


	_.chunk(['a', 'b', 'c', 'd', 'e', 'f'], 2);
//-->[ [ 'a', 'b' ], [ 'c', 'd' ] ]

	_.chunk(['a', 'b', 'c', 'd', 'e'], 3);
//-->[ [ 'a', 'b', 'c' ], [ 'd', 'e' ] ]

Compact Method

Goal: make an array from given with all falsy values removed
My JS Implementation 

							function myCompact(arr) {
								const output = [];
								arr.forEach(element => {
									if (element) {
										output.push(element)
									}
								});
								return output;
							}
							myCompact([0, 1, false, 2, '', 3, NaN, null, undefined]);
							//--> [ 1, 2, 3 ]
Lodash Method 

_.compact([0, 1, false, 2, '', 3, NaN, null, undefined]);

//--> [ 1, 2, 3 ]

Intersection Method

Goal: find common values in two arrays and return new array with these values
My JS Implementation 

							function myIntersection(arr1, arr2) {
								return arr1.filter(x => arr2.includes(x));
							}

							let a = {b: 1}
							let b = a

							myIntersection([2, 1], [2, 3]);
							//--> [2]
							myIntersection([5, 2, 1, 4], [2, 3, 4, 5]);
							//--> [ 5, 2, 4 ]
							myIntersection([a], [b]);
							//-->[ { b: 1 } ]
Lodash Method 

let a = {b: 1}
let b = a

_.intersection([2, 1], [2, 3]);
//--> [2]
_.intersection([5, 2, 1, 4], [2, 3, 4, 5]);
//--> [ 5, 2, 4 ]
_.intersection([a], [b]);
//-->[ { b: 1 } ]

Size

Goal: get the size of given collection
My JS Implementation 

							function mySize(collection) {
								if (!Array.isArray(collection)) {
									return Object.keys(collection).length
								} else {
									return collection.length
								}
							}

							mySize([1, 2, 3]);
							//--> 3
							mySize({ 'a': 1, 'b': 2 });
							//--> 2
							mySize('pebbles');
							//--> 7
Lodash Method 

_.size([1, 2, 3]);
//--> 3

_.size({ 'a': 1, 'b': 2 });
//--> 2

_.size('pebbles');
//--> 7

Thank you for your attention!