Thursday, November 13, 2025
HomeLanguagesJavascriptCollect.js whereInstanceOf() function

Collect.js whereInstanceOf() function

The whereInstanceOf() function is used to filter input with a given class type.  In JavaScript, the array is first converted to a collection and then the function is applied to the collection.

Syntax: 

data.whereInstanceOf('key')

Parameters: This function accepts a single parameter as mentioned above and described below:

  • Key: This parameter holds the key name that defines the value of that key.

Return value: Return the collection with a key value that was mentioned.
Below examples illustrate the whereInstanceOf() function in collect.js
Example 1: Here in this example, we take a collection and then using the whereInstanceOf() method we have returned filtered collection using the key.

Javascript




// It is used to import collect.js library
const collect = require('collect.js');
  
const Input = collect([
  new Books('Pride and prejudice'),
  new Books('The Great Gatsby '),
  new Movies('It'),
]);
  
const output = Input.whereInstanceOf(Books);
console.log(output.all());


Output: 

[
   new Books('Pride and prejudice'),
   new Books('The Great Gatsby'),
]

Example 2: Same thing we have done here as the above example.

Javascript




// It is used to import collect.js library
const collect = require('collect.js');
  
const Input = collect([
  new Year('1980'),
  new Year('2020'),
  new Name('Mohan'),
]);
  
const output = Input.whereInstanceOf(Name);
  
console.log(output.all());


Output: 

[
  new Name('Mohan'),
]

References: https://collect.js.org/api/whereinstanceof.html

Whether you’re preparing for your first job interview or aiming to upskill in this ever-evolving tech landscape, neveropen Courses are your key to success. We provide top-quality content at affordable prices, all geared towards accelerating your growth in a time-bound manner. Join the millions we’ve already empowered, and we’re here to do the same for you. Don’t miss out – check it out now!
RELATED ARTICLES

Most Popular

Dominic
32399 POSTS0 COMMENTS
Milvus
95 POSTS0 COMMENTS
Nango Kala
6765 POSTS0 COMMENTS
Nicole Veronica
11916 POSTS0 COMMENTS
Nokonwaba Nkukhwana
11984 POSTS0 COMMENTS
Shaida Kate Naidoo
6889 POSTS0 COMMENTS
Ted Musemwa
7141 POSTS0 COMMENTS
Thapelo Manthata
6837 POSTS0 COMMENTS
Umr Jansen
6839 POSTS0 COMMENTS