Fix the crash when hashing an async function

[whatisaphone]

Fixes #67.

This code will no longer crash:

objectHash(async function foo () {})

[whatisaphone]

I had to add a workaround for the old browserify build system. There's already one workaround there, so a second didn't seem too bad. The workaround only applies to the bundled code run with Karma. The tests run from Node still run with the original non-bundled code.

The tests pass for everything except Node 6, which didn't support async functions. Node 6 reached end-of-life back in April. Maybe it's time to drop support for it?

[whatisaphone]

Node 6 reached EOL last decade. The tests pass for Node >= 8.

That probably means a major version bump. There are no other breaking changes.

[agilgur5]

@addaleax any word on this? Currently facing this problem in TSDX in several issues: jaredpalmer/tsdx#294 , jaredpalmer/tsdx#358 (comment) , jaredpalmer/tsdx#278 (comment) , and a few in jaredpalmer/tsdx#379

TSDX is using object-hash via rollup-plugin-typescript2, where there's an old issue around this (ezolenko/rollup-plugin-typescript2#105) and the current fix/workaround is to disable caching, which is very suboptimal. Would be great to actually fix this bug instead of having a hacky workaround!

You had said you would look into this back then in #68 (comment) and then there was never an update (@wessberg moved on to make a competing plugin that seems to have some custom hashing? or something).

This approach should also work for async generator functions as they come out as 'asyncgeneratorfunction'.
A similar approach is mentioned in tc39/proposal-async-await#78 (comment) for programmatic detection of async functions as well (the cons aren't relevant to this use case -- toString and everything still work).

[arvinsim]

@agilgur5 I was happily using TSDX until I tried to use rollup-plugin-visualizer to measure my bundle sizes when I got this error. While it is not urgent right now, it would be nice if they can fix this seemingly annoying issue.

[agilgur5]

@arvinsim It is one of the top issues in TSDX, particularly with how frequently it's referenced. A good chunk of people are definitely using the rpts2 workaround that disables caching, which is a poor developer experience. That's why I chimed in here as I believe it's pretty high priority for TSDX to fix.

And unfortunately it can't be monkey-patched and can't easily be patched with a fork as it's a transitive dependency 😕

[addaleax]

Yeah, all I need to do is to fix this test up so that instead of the last commit there is actual support for Node.js 6 … will do that now

[addaleax]

Should be fixed in v2.0.2 now

[agilgur5]

Thanks so much for the quick response & release @addaleax !!