Javascript find index of word in string (not part of word)

user759885 picture user759885 · Oct 8, 2012 · Viewed 16.5k times · Source

I am currently using str.indexOf("word") to find a word in a string. But the problem is that it is also returning parts of other words.

Example: "I went to the foobar and ordered foo." I want the first index of the single word "foo", not not the foo within foobar.

I can not search for "foo " because sometimes it might be followed by a full-stop or comma (any non-alphanumeric character).

Answer

Blender picture Blender · Oct 8, 2012

You'll have to use regex for this:

> 'I went to the foobar and ordered foo.'.indexOf('foo')
14
> 'I went to the foobar and ordered foo.'.search(/\bfoo\b/)
33

/\bfoo\b/ matches foo that is surrounded by word boundaries.

To match an arbitrary word, construct a RegExp object:

> var word = 'foo';
> var regex = new RegExp('\\b' + word + '\\b');
> 'I went to the foobar and ordered foo.'.search(regex);
33