"Is this code loaded *asynchronously* (i.e. non-blocking), or just *lazily*? There's quite a difference between the two. If var GraphView = require("./graph-view"); (from the example) remains the same, I can't see how this can be loaded asynchronously. If it's loaded synchronously, then I expect the entire UI thread to block only until the "graph.js" bundle has been loaded. Not a really nice user experience at that point." - Meryn Stol