No closures

[mcollina]

includes #21.

I have used bind in some cases where perf was not needed and we needed to pass some parameters to the function. bind is as fast as creating a closure in the latest V8, but it is not hoisted and so we avoid it altogether for the happy-path.

[jasnell]

Want to close #21 since this includes it?

[mcollina]

@jasnell yes.

@evanlucas adresses.

[mcollina]

@evanlucas @jasnell I moved away from Map() and converted it back to {}. It should solve most of the issues. Unfortunately for-of loops are really slow :(.

[evanlucas]

@mcollina won't moving back to an object prevent setting headers like __proto__?

[mcollina]

@evanlucas this is the behavior that we have on require('http'), and it is faster than Map for iterating over all the pairs in the map.

https://github.com/nodejs/node/blob/master/lib/_http_outgoing.js#L365

There is PR to change that, see nodejs/node#6102.

[targos]

I suppose http2 support won't land before v8.0.0? By that time, we will have a much more recent version of V8 in which the for-of loop could be fast enough.
I think we should'nt make those engine-related micro optimizations too early.

[mightyiam]

I like what @targos is saying. Optimise as required, when required.

[mcollina]

I strongly disagree. There are both perf and compatibility issue with http1 -> see the discussion there.
As far as I understand, there is no magical "for of" optimization landing anytime soon in V8.

This particular code makes no sense if it is not as fast as possible.

[jasnell]

@mcollina ... switching away from Map is fine but I think using a prototype-less object (Object.create(null)) would be better. We wanted to make such a change in the http/1 stuff but haven't been able to due to backwards compatibility issues that we simply do not have in this case. Using the prototype-less object allows us to not have to deal with issues like __proto__

[jasnell]

@targos: the goal is to get this into 8.x as close to 8.0.0 as possible as experimental.

[mcollina]

@jasnell should be good now. Please review.

[jasnell]

@mcollina ... I'm going to get this landed so I can start building off of it.

[jasnell]

Landed!