javascript - Can anyone explain this regular expression -

javascript - Can anyone explain this regular expression -

i came across 1 article john resig explaining javascript inheritance. http://ejohn.org/blog/simple-javascript-inheritance/

in post there class implementation code starting line has regexp

fntest = /xyz/.test(function(){xyz;}) ? /\b_super\b/ : /.*/;

can 1 tell me meaning of this?

the fntest used check whether method uses _super somewhere. that, function implicitly converted string (tostring) , tested against regular look (in // re-create properties on onto new prototype).

however, not implementations yield source code of function when it's tostring method called. test checks whether function(){xyz;} can tested against containing xyz - if not, always-matching /.*/ used instead of /\b_super\b/.

javascript regex