javascript - Why does string.match(...)[0] throws an exception? -

javascript - Why does string.match(...)[0] throws an exception? -

i'm trying pull first occurence of regex pattern string in 1 statement create code cleaner. want do:

var matchedstring = somestring.match(/some regex/g)[0];

i expect legal throws exception:

exception: somestring.match(...) null

it seems js trying index array before match finsihed, array provide atleast 1 match, don't expect null.

i insight in why happens. bug?

my machine pc running arch linux x86_64. code beingness executed within scratchpad of firefox 32.0.3.

thanks interest.

if somestring.match() finds no match, returns null.

and, null[0] throws exception.

since getting exact exception, regex not beingness found in content. careful using g flag on match alternative in way not expect when have submatches specified in regex. since looks want first match anyway, should remove g option.

a safer way code is:

var matches = somestring.match(/some regex/); if (matches) { // here matches[0] }

javascript regex string match