Collect.js macro() Method

The macro() method is used to register a custom method. This method used the custom function.

Syntax:

collect(array).macro()

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

Return Value: This method returns the collection keys.

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

Example 1:

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

collect().macro('even', function () {
    return this.map(element => element % 2 == 0);
});

const arr = [2, 3, 5, 6, 8, 9, 10, 12, 13, 16];

const collection = collect(arr);

console.log(collection.even());

Output:

Collection {
  items: [
    true, false, false,
    true, true,  false,
    true, true,  false,
    true
  ]
}

Example 2:

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

collect().macro('uppercase', function () {
    return this.map(element => element.toUpperCase());
});

const arr = ['gfg', 'geeks', 'GeeksforGeeks'];

const collection = collect(arr);

console.log(collection.uppercase());

Output:

Collection { items: [ 'GFG', 'GEEKS', 'GEEKSFORGEEKS' ] }