AgentJs Candid Pinpointed Type Errors upgrade - PR

Developers
1

I often stumble upon horrible Candid errors which take up to 1 hour to figure.

For me personally, that’s one of the worst parts of the dev experience, so now that I know how things work better, I went and fixed it.

When it occurs: Writing dapps with agentjs, using nested structures in your calls, and not providing correct input.

Before: You basically get the whole record dumped with no specific reason given
Example:

image
image1626×554 143 KB

Pull Request:
Errors look like this now:

[Error: Invalid record {arg:vec nat8; wasm_module:vec nat8; mode:variant {reinstall; upgrade; install}; canister_id:principal} argument: 

field canister_id -> Invalid principal argument: "rrkah-fqaaa-aaaaa-aaaaq-cai"]
  1. It follows the nested structure and chains thrown errors, so no matter how deep you go, you will see where the problem is - pinpointed.
  2. Cuts long values (you don’t want a 2mb blob inside your error)
  3. Works with the current tests and shouldn’t introduce breaking changes
2

Thanks for taking the time to write this up. Definitely not great experience. Let me ping folks who may know more so they are aware.

3

Maybe it’s not that bad for Typescript users, since they should be getting type errors. And perhaps that’s why it was under the radar.