wp-rest-api-allow-all-cross-origin-requests.php

<?php

/*
 * Plugin Name: WP REST API - Allow All CORS Requests
 * Description: Adds headers to allow cross-origin requests to the WordPress REST API.
 * Version: 1.0
 * Plugin URI: https://gist.github.com/wpscholar/59f5708cba291a314375b2dedd104e1e
 * Author: Micah Wood
 * Author URI: https://wpscholar.com
 */

add_action( 'rest_api_init', function() {
    
	remove_filter( 'rest_pre_serve_request', 'rest_send_cors_headers' );
  
	add_filter( 'rest_pre_serve_request', function( $value ) {
		header( 'Access-Control-Allow-Origin: *' );
		header( 'Access-Control-Allow-Methods: POST, GET, OPTIONS, PUT, DELETE' );
		header( 'Access-Control-Allow-Credentials: true' );

		return $value;
		
	});
  
}, 12 );