Revert compact() back to an array filter()
Revert compact() back to an array filter()

ESLint pointed out the redundant double negation to me when I tried to
update it to the latest version. Looking at the commit that introduced
this, it seems as though I wrote this function to appease Flow. However,
now it seems that Flow is able to understand the array filter so we can
go back to using it.

Galooshi/import-js,trotzig/import-js,trotzig/import-js,trotzig/import-js