graphql-anywhere: replace `JSON.stringify` call on very hot code path

Hey, folks! We use the propType module from graphql-anywhere in quite a few places in our app & we’re finding that the JSON.stringify call here causes a noticeable slowdown when we make a particularly large data request during local development (ie, when prop-type checking is performed).

The size of our returned data is relatively large and contains many nested types in its query, which I suppose is what’s causing this code path to be so hot.

Here’s what I see when using Chrome’s performance profiling feature after making a couple of these large network requests:

I replaced this JSON.stringify call with a hard-coded string for comparison, which drove this line’s execution time to 10s of ms.

Using JSON.stringify is nice for the level of detail it gives in the error, but would you accept an alternative that makes this line run faster? Using JSON.stringify causes such a large slowdown during local development that I think we’ll have to remove this package from our app if a change isn’t possible.

A simple solution might be to just make the error ${info.resultKey} missing.

Happy to make a PR if you’d be open to it!

[benjamn]

I’m open to improving this, but I would just point out that we (the Apollo Client team) thought we had written the code such that JSON.stringify would not be called in production, where performance matters most, thanks to ts-invariant and rollup-plugin-invariant.

This issue is specifically pointing out that JSON.stringify is called unnecessarily in development, which is true, but the stringification payload needs to be pretty huge before that becomes a noticeable problem, and there’s no performance penalty in production, because long error messages are stripped in production builds.

Also, just in case anyone who reads this is new to JavaScript performance, JSON.stringify is one of the most obsessively optimized tools we have available to us as web developers, so in general there’s no way to do what it does any faster with handwritten JS. You can only pass less data to it, or stop calling it unnecessarily, which is what we’re considering doing here.

[hwillson]

Closing since graphql-anywhere is no longer something we’re supporting (details: https://github.com/apollographql/apollo-client/issues/5744#issuecomment-571988792). Thanks!