The expression $map_class of type string|null is loosely compared to false; this is ambiguous if the string can be empty. You might want to explicitly use === null instead.
In PHP, under loose comparison (like ==, or !=, or switch conditions),
values of different types might be equal.
For string values, the empty string '' is a special case, in particular
the following results might be unexpected:
''==false// true''==null// true'ab'==false// false'ab'==null// false// It is often better to use strict comparison''===false// false''===null// false
FileEye /
MimeMap
In PHP, under loose comparison (like
==, or!=, orswitchconditions), values of different types might be equal.For
stringvalues, the empty string''is a special case, in particular the following results might be unexpected: