Collect.js countBy() Method

The countBy() method is used to count the occurrence of values in the collection. This method counts the occurrence of every element.

Syntax:

collect(array).countBy()

Parameters: The collect() method takes one argument that is converted into the collection and then countBy() method is applied on it.

Return Value: This method returns the count of occurrence of values in the collection.

Below example illustrate the countBy() method in collect.js:

Example 1:

Javascript

// It is used to import collect.js library
const collect = require('collect.js');

const num = [0, 1, 1, 2, 3, 4, 4, 5, 5, 5, 5, 5];
const data = collect(num);

const total = data.countBy();

console.log({ total });

Output:

{
 total: Collection {
   items: { '0': 1, '1': 2, '2': 1, '3': 1, '4': 2, '5': 5 }
 }
}

Example 2:

Javascript

const collect = require('collect.js');

const collection = collect([
    'geeks@gmail.com',
    'aman@gmail.com',
    'krk@gmail.com',
    'abc@gfg.com',
    'demo@gfg.com',
    'hr@geeksforgeeks.org'
]);

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

console.log(counted.all());

Output:

{ 'gmail.com': 3, 'gfg.com': 2, 'geeksforgeeks.org': 1 }