Set CORS Header for WordPress JSON API

wordpress-cors.php

<?php
add_action( 'init', 'handle_preflight' );
function handle_preflight() {
    header("Access-Control-Allow-Origin: " . get_http_origin());
    header("Access-Control-Allow-Methods: POST, GET, OPTIONS, PUT, DELETE");
    header("Access-Control-Allow-Credentials: true");
    header("Access-Control-Allow-Headers: Authorization, Origin, X-Requested-With, Content-Type, Accept");
    if ( 'OPTIONS' == $_SERVER['REQUEST_METHOD'] ) {
        status_header(200);
        exit();
    }
}?>