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.
// 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.
// 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());