Replace invariant with inline throw error for production build?

[syranide]

Error: Minified exception occurred; use the non-minified dev environment for the full error
message and additional helpful warnings. in /build.js on line (of invariant implementation)

Perhaps there are larger issues preventing this, but considering production errors encountered by a user rarely has access to stack traces, so you only get the single top-level error location... if an error is thrown by React today that's all you know, an error was thrown.

It would be nice if invariant(...) was replaced with if (...) throw new Error(...) instead. I could then report vaguely meaningful error locations which could at least hint at what the error is, React would also avoid the invariant invocation overhead then.

cc @zpao @sebmarkbage @spicyj

[gaearon]

See also #2686

[sebmarkbage]

I think something like #2686 is a better solution. E.g. surfacing an error code or something in production. Maybe a hash of the original message.

The reason I don't think invariant(...) matters is that these checks often end up in common validation helpers. This is particularly common for warnings but also for invariants. We shouldn't have to take the levels of the stack trace into account when structuring our internal code. So even if we moved it one level, the next level will still be problematic.

Besides, you can catch complete stack traces in production in most browsers. That should be part of your error message / logging solution. That will give you much better error messages anyway since you can track the source in your own code easier.

*) We have experimented with converting invariant(...) to if (...) throw using a transpiler. That has shown to be a performance boost. We can also safely strip the error message for production builds. Especially in non-JIT environments and since a lot of our code currently deopts. That's unrelated to the problem of stack traces though.