Collect.js keyBy() Method

The keyBy() method is used to keys the collection elements by the given key. If the collection contains multiple items with same key then the last element will appear.

Syntax:

collect(array).keyBy(key)

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

Return Value: This method returns the collection elements by given key value.

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

Example 1:

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

let obj = [
    {
        name: 'Rahul',
        score: 98,
    },
    {
        name: 'Aditya',
        score: 96,
    },
    {
        name: 'Abhishek',
        score: 80
    }
];

const collection = collect(obj);

const key_val = collection.keyBy('name');

console.log(key_val.all());

Output:

{
  Rahul: { name: 'Rahul', score: 98 },
  Aditya: { name: 'Aditya', score: 96 },
  Abhishek: { name: 'Abhishek', score: 80 }
}

Example 2:

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

let obj = [
    {
        name: 'Rahul',
        dob: '25-10-96',
        section: 'A',
        score: 98,
    },
    {
        name: 'Aditya',
        dob: '25-10-96',
        section: 'B',
        score: 96,
    },
    {
        name: 'Abhishek',
        dob: '16-08-94',
        section: 'A',
        score: 80
    },
    {
        name: 'Rahul',
        dob: '19-08-96',
        section: 'B',
        score: 77,
    },
];

const collection = collect(obj);

const key_val = collection.keyBy('dob');

console.log(key_val.all());

Output:

{
  '25-10-96': { 
    name: 'Aditya', dob: '25-10-96', 
    section: 'B', score: 96 
  },
  '16-08-94': { 
    name: 'Abhishek', dob: '16-08-94', 
    section: 'A', score: 80 
  },
  '19-08-96': { 
    name: 'Rahul', dob: '19-08-96', 
    section: 'B', score: 77 
  }
}