zone

> I'm really unclear on how the zone library is doing the magical interception of errors It monkey patches the entry points into javascript from the binding layer (some wrapping happens at a higher level), for the purpose of keeping track of the active zone. At that level we also wrap a try-catch block around all callbacks. > Does a library (say, one that came from npm and not the core library) have to be zone-aware to function correctly with zones It depends. Most modules shouldn't need any modification. However there are certain not-so-common cases (for example, when you're implementing a connection pool) that the module would need to be made zone-aware. It's necessary when the module wants to call a callback (or any function) in a child zone from a parent/ancestor zone. Right now that's not very easy - you'd have to use a Gate (https:

https://github.com/strongloop/zone/blob/master/showcase/long... <- this is the line I was referring to. I can see why it's doing it, actually, because the connection is presumably done at that point and an error after everything important is done is less important, but it's poorly explained at best (as being to prevent the 'zone from exploding').