Q+D CORS headers for WP REST API

wp-cors.php

<?php
/**
 * Plugin Name: CORS
 * Description: Just adds headers to every response to enable cross-origin GET requests for API.
 * Version: 0.0.1
 * Author: NJI Media
 * Author URI: https://www.njimedia.com
 * License: GPLv2 or later
 * Text Domain: cors
 *
 * @package WordPress
 * @subpackage CORS
 */

// Hook in.
add_action( 'init', 'add_cors_headers' );

/**
 * Add CORS headers to all responses.
 */
function add_cors_headers() {
	header( 'Access-Control-Allow-Origin: *' );
	header( 'Access-Control-Allow-Methods: GET' );
}