lib/graph/make_graph_with_bundles.js
function copyIfSet(src, dest, prop) {
	if (src[prop]) {
		dest[prop] = src[prop];
	}
}
function copyIfSet(src, dest, prop) {
	if (src[prop]) {
		dest[prop] = src[prop];
	}
}
function copyIfSet ( src , dest , prop ) { if ( src [ prop ] ) { dest [ prop ] = src [ prop ] ; } }
If `prop` exists in the `src` object, it copies its value to `dest`
If prop exists in the src object it copies its value to dest