Set map address from custom field "Street Address" if page/post has one, on Flexible Map plugin for WordPress

flxmap-custom-address.php

<?php
/*
Plugin Name: Flxmap Custom Address
Plugin URI: https://gist.github.com/webaware/9927981
Description: Set map address from custom field "Street Address" if page/post has one
Version: 1
Author: WebAware
Author URI: http://webaware.com.au/

@ref http://wordpress.org/support/topic/flexiblemap-address-using-data-from-custom-field
*/

/**
* @param array $attrs shortcode attributes for map
* @return array
*/
add_filter('flexmap_shortcode_attrs', function($attrs) {
    global $post;

    if ($post) {
        $address = get_post_meta($post->ID, 'Street Address', true);
        if ($address) {
            $attrs['address'] = $address;
        }
    }

    return $attrs;
});