Collect.js where() Function

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The where() function is used to filter the collection by a given key or value contained within the given array. In JavaScript, the array is first converted to a collection and then the function is applied to the collection.

Syntax:

data.where('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 where() function in collect.js:

Example 1: Here in this example, we take a collection and then using the where() method we have returned filtered collection using the key.

Javascript

// It is used to import collect.js library
 
const collection = collect([
  { Book: 'Let US C', price: 2000 },
  { Book: 'Begin Python', price: 1000 },
  { Book: 'Learn the DEV', price: 1500 },
]);
 
const filtered = collection.where('price', [1000, 1500]);
filtered.all();

Output:

[
 { Book: 'Begin Python', price: 1000 },
 { Book: 'Learn the DEV', price: 1500 }
]

Example 2:

Javascript

// It is used to import collect.js library 
const collect = require('collect.js'); 
 
const Input = collect([ 
  new Year('1980'), 
  new Year('2020'), 
  new Year('2025'), 
]); 
 
const output = Input.where('Year',[2000, 2025]); 
 
console.log(output.all());