Trouble with generators and iterators

[brainkim]

I’m consistently having strange bugs related to Crank.js projects in codesandbox. The projects will work in a parcel 1 app locally, but when I try to upload them to codesandbox they stop working.

For instance take this sandbox: https://codesandbox.io/s/crankjs-threejs-boxes-demo-ypyqi?file=/src/crank-three.tsx:5867-5904

Works locally, but once I copied the files into the sandbox, iteration over this just stopped working for one file. Weird I think, maybe they’re not downleveling iteration with TypeScript. So I do that and all of a sudden some variable in another scope is undefined, when it’s never unassigned within the loop.

These bugs are scary and completely unintrospectable, and I suspect they have to do with outdated versions of regeneratorRuntime/babel. Is there somewhere I can get more information/debug what the code is actually being compiled to?

[CompuIves]

Hmm, this is indeed very weird. It could maybe be because we use the main module instead of the esmodule in Three context. I've seen discussions around this before. Is this only in Three projects, or any project?

[brainkim]

I’ve also seen a similar issue where I tried to destructure an iterator in a variable for ({variable} of this) where, if the variable name was different it wouldn’t error, as in, it would only error for a specific identifier. I don’t remember the variable name, and I apologize for not capturing and shrinking the bug when I found it. I suspect these are issues related to code sandbox’s compilation pipeline? How would I begin investigating this in the repository? If I encounter any more bugs I will definitely try to shrink them, I just didn’t have the time.