<?php
define( 'FRONTPAGE_BUDDY_REST_ROUTE_NAMESPACE', 'frontpage-buddy/v1' ); 
...
...
$data = apply_filters(
    'frontpage_buddy_script_data',
    array(
        'config'      => array(
            'rest_url_base' => rest_url( FRONTPAGE_BUDDY_REST_ROUTE_NAMESPACE ),
            'rest_nonce'    => wp_create_nonce( 'wp_rest' ),
        ),
        ...
        ...
        'object_type' => '',
        'object_id'   => 0,
    )
);

wp_add_inline_script(
    'frontpage-buddy-editor',
    'var FRONTPAGE_BUDDY = ' . wp_json_encode( $data ) . ';',
    'before'
);