Add Google Maps API key to enqueued script in WordPress

add_google_maps_key.php

<?php
if ( ! function_exists( 'inspiry_google_maps_api_key' ) ) :
	/**
	 * This function adds API key ( if provided in settings ) to google maps arguments
	 */
	function inspiry_google_maps_api_key( $google_map_arguments ) {
		/* Get Google Maps API Key if available */
		$google_maps_api_key = get_option( 'inspiry_google_maps_api_key' );
		if ( ! empty( $google_maps_api_key ) ) {
			$google_map_arguments[ 'key' ] = urlencode( $google_maps_api_key );
		}

		return $google_map_arguments;
	}

	add_filter( 'inspiry_google_map_arguments', 'inspiry_google_maps_api_key' );
endif;

google_maps_enqueue.php

<?php
                /* default map query arguments */
                $google_map_arguments = array ();

                // Google Map API
                wp_enqueue_script(
                    'google-map-api',
                    esc_url_raw(
                        add_query_arg(
                            apply_filters(
                                'inspiry_google_map_arguments',
                                $google_map_arguments
                            ),
                            '//maps.google.com/maps/api/js'
                        )
                    ),
                    array(),
                    '3.21',
                    false
                );

Good Work!