Your note about 'async-lock' NPM package clears up the confusion. That's used to serialize operations to external systems, with their readme showing an example with multiple Redis calls within await blocks setting the same key incorrectly.

This conversation was talking about access to variables and data within Javascript code itself. Any language is open to data races when dealing with external systems. I can see why having a `lock` construct can be helpful here, but it seems extraneous when the actual language doesn't support concurrent access and simple packages already exist. The 'async-lock' is just a wrapper around a few variables, and only works precisely because JS is already single-threaded and serialized.