It looks like our coding conventions on PHP and JS have diverged on the issue of spaces inside of brackets. Manual:Coding conventions/PHP#Spaces states we should not do $c = $a[ 0 ];, but Manual:Coding conventions/JavaScript#Spaces states that we should, and it is one of the rules and autofixes in eslint-config-wikimedia.
Should we perhaps pick one way of doing it, then update the other coding convention page and linter to also do it that way, for consistency?