How to take benefit of #6647

bp-custom.php

<?php
/**
 * Just a quick and dirty example!
 */ 
function test_attachment_js_actions() {
	?>
	<script type="text/javascript">
		if ( 'undefined' !== typeof window.bp )  {
			if ( window.bp.Avatar ) {
				bp.Avatar.Attachment.on( 'change:url', function( data ) {
					console.log( data.attributes );
				} );
			}

			if ( window.bp.CoverImage ) {
				bp.CoverImage.Attachment.on( 'change:url', function( data ) {
					console.log( data.attributes );
				} );
			}
		}
	</script>
	<?php
}
add_action( 'wp_footer', 'test_attachment_js_actions', 1000 );