Bug 159528 – Use Array.forEach in Headers built-in constructor

• Component: WebCore Misc.
• Status: RESOLVED FIXED

[youenn fablet]

Array.forEach can be used if it is shielded from public scripts.

[youenn fablet]

Created attachment 283068 [details]
Patch

[Mark Lam]

Comment on attachment 283068 [details]
Patch

View in context: https://bugs.webkit.org/attachment.cgi?id=283068&action=review

> Source/WebCore/Modules/fetch/FetchHeaders.js:44
> +        @Array.prototype.@forEach.@call(headersInit, (header) => {

Is this required by the spec?  If not, is there a perf implication to this change?

[youenn fablet]

(In reply to comment #2)
> Comment on attachment 283068 [details]
> Patch
> 
> View in context:
> https://bugs.webkit.org/attachment.cgi?id=283068&action=review
> 
> > Source/WebCore/Modules/fetch/FetchHeaders.js:44
> > +        @Array.prototype.@forEach.@call(headersInit, (header) => {
> 
> Is this required by the spec?  If not, is there a perf implication to this
> change?

No, it is not required and I do not think this makes any perf improvement since Array.forEach is using a for loop as well.
This just makes the code smaller here.

[Mark Lam]

Comment on attachment 283068 [details]
Patch

View in context: https://bugs.webkit.org/attachment.cgi?id=283068&action=review

>>> Source/WebCore/Modules/fetch/FetchHeaders.js:44
>>> +        @Array.prototype.@forEach.@call(headersInit, (header) => {
>> 
>> Is this required by the spec?  If not, is there a perf implication to this change?
> 
> No, it is not required and I do not think this makes any perf improvement since Array.forEach is using a for loop as well.
> This just makes the code smaller here.

My concern is that it makes the code slower because you're adding a call to forEach which is not free, and it doesn't appear to be that much smaller.  But maybe it's not such a big deal here.  Just thought I'd ask.

[youenn fablet]

Values iterator with a for-of loop seems a bit less expensive but it is still creating an iterator object. Maybe this is not worth it.

[youenn fablet]

We no longer use builtins for creating headers thanks to improvement in the binding generator.