Position of first word of string in Javascript

Question

I originally used indexOf to find a space but I want to find any word boundary.

Something like this, but what regex?

var str = "This is a sentence",
firstword = str.search("");
return word;

I want to return "This". Even in the case of a tab, period, comma, etc.

Answer 1

Something like this:

var str = "This is a sentence"; 
return str.split(/\b/)[0];

Although you would probably want to check that there was a match like this:

var str = "This is a sentence"; 
var matches = str.split(/\b/);
return matches.length > 0 ? matches[0] : "";

Answer 2

This splits the string at every word boundary and returns the first one:

var str = "This is a sentence";
firstword = str.split(/\b/)[0];