Question

From “Javascript: the Good Parts”: the Good Parts:

Avoid /* … */ for comments, */ appears in useful constructs in javascript. Use //.

I’m curious as to what these “useful constructs” might be, as I can’t think of any OTOH (except maybe a regex like /.*/?)

Answer 1

The blogger was trying to abbreviate what Crockford wrote at JavaScript: The Good Parts, Chapter number 2 ( Grammar ). This topic comes on the last paragraph of the first section ( Whitespace ). It says,

The /* */ form of block comments came from a language called
PL/I. PL/I chose those strange pairs as the symbols for comments
because they were unlikely to occur in that language’s programs,
except perhaps in string literals. In JavaScript, those pairs
can also occur in regular expression literals, so block comments are
not safe for commenting out blocks of code. For example:

 /* 
     var rm_a = /a*/.match(s); 
 */ 

causes a syntax error. So, it is recommended that /* */ comments be
avoided and // comments be used instead. In this book, // will be
used exclusively.