Add name property to custom error classes

[rashfael]

Adding the name property to custom errors would help us with serializing errors and re-throwing TerminalErrors through user-defined code sandboxes. Otherwise name on these custom errors is just Error.

[igalshilman]

Hello @rashfael,
I didn't get exactly what is the issue that this PR solves? what are user-defined code sandboxes?
Does checking for instanceof / typeof doesn't cut it?

[rashfael]

We're running user code and no-code runners as wasm components that can call apis on the host. For example if we throw a TerminalError inside our database update api the call stack looks like this:

• Service / host
• wasm guest
• Host API

Every time we cross the boundary to wasm (so if the host calls wasm or wasm calls the api) we are serializing/deserializing the payload through json, including errors. If the host api throws an error, it needs to pass through the boundary twice.

When serializing we loose the js prototype chain and instanceof doesn't work anymore.
On the service side we re-instantiate TerminalErrors whenever we can so the restate sdk can check instanceof again.

Currently we try to serialize error.constructor.name, which is a bit hacky though (and minifiers are usually not preserving constructor names without being told).

Setting name would help us and be in line with built-in errors. (new TypeError()).name for example is TypeError.

[igalshilman]

Understood, thanks for the explanation!