Add potential items directly to a single array with two indexOf
checks.
Previously, potential items were first put in a new temporary array,
then that array was filtered with indexOf checks into another temporary
array, and then the result of that combined with the previous results
into another temporary filtered array, and then the previous results
array replaced with the new one. This eliminates 2*2N filter+concat
calls an their overhead from calling functions, creating arrays,
copying arrays and the memory for those arrays. (Where N is the number
of language-list strategies). It also reduces the total number of
indexOf calls.
Below is a comparison of time spent in createCompactList() during
page load process, compared to master without this and the previous
commit. Measured on localhost with Vector, EventLogging, Interwiki,
and ULS installed; on a page that is a copy of en.wikipedia.org/Messier_87
and its 51 interlanguage links. This page was a featured article
last week. Its count of links seems average compared to other
featured and/or most-viewed articles last week (the other ones
I checked had 23, 43, 52, and 76 langlinks respectively).
|--------------|----------|--------|
| | Before | After |
|--------------|----------|--------|
| Chrome 69 | 77.5ms | 41.4ms |
| MacBook Pro | 57.7ms | 44.4ms |
| CPU 1/6th | 63.8ms | 45.3ms |
|--------------|----------|--------|
| Firefox 61 | 12ms | 10ms |
| | 10ms | 9ms |
| | 11ms | 8ms |
|--------------|----------|--------|
| Safari 11 | 3.5ms | 2.7ms |
| | 3.3ms | 2.6ms |
| | 3.4ms | 2.8ms |
|--------------|----------|--------|
Bug: T127328
Change-Id: I56052e7c01c6a667500773e12c755a7a5f5d9cd0
fcfa36ac77