code: function regenerate(moduleName, done){
  		var cfg = clone(config, true);
  		// if the moduleName is not in the graph, make it the main.
  		if(moduleName && !cachedData.graph[moduleName]) {
  			cfg.main = moduleName;
  		}
  
  		makeBundleGraph(cfg, options).then(function(data){
  			var graph = data.graph;
  			var oldGraph = cachedData ? cachedData.graph : {};
  			for(var name in graph){
  				if(name !== moduleName && oldGraph[name]) {
  					graph[name].transforms = oldGraph[name].transforms;
  				}
  			}
  			cachedData = cloneData(data);
  			done(null, data);
  		}, done);
  	}
docs: Regenerate a new bundle graph and copy over the transforms so they can be reused.