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

Question

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 1

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

Answer 2

For a general case, use the RegExp constrcutor to create the regular expression bounded by word boundaries:

function matchWord(s, word) {
  var re = new RegExp( '\\b' + word + '\\b');
  return s.match(re);
}

Note that hyphens are considered word boundaries, so sun-dried is two words.

Answer 3

I have tried both with ".search" and ".match", as suggested in the previous answers, but only this solution worked for me.

var str = 'Lorem Ipsum Docet';
var kw  = 'IPSUM';
var res = new RegExp('\\b('+kw+')\\b','i').test(str);

console.log(res); // true (...or false)

With the 'i' for case insensitive search.

ComFreek wrote a detailed answer here