What is count() and countBy() methods in Collect.js?

Collect.js - Interview Questions

count() : The count() method returns the total number of items in the collection.

const collection = collect([1, 2, 3, 4]);

collection.count();

// 4

countBy() : The countBy() method counts the occurences of values in the collection. By default, the method counts the occurrences of every element:

const collection = collect([1, 2, 2, 2, 3]);

const counted = collection.countBy();

counted.all();

// {
//   1: 1,
//   2: 3,
//   3: 1,
// }

However, you pass a callback to the countBy() method to count all items by a custom value:

const collection = collect([
  'freetimelearn@gmail.com',
  'info@freetimelearning.com',
  'vvramanareddy9963@gmail.com',
]);

const counted = collection.countBy(email => email.split('@')[1]);

counted.all();

// {
//   'gmail.com': 2,
//   'freetimelearning.com': 1,
// }