Search for a whole word in a string

Question

I am looking for a function written in JavaScript (not in jQuery) which will return true if the given word exactly matches (should not be case sensitive).

Like...

var searchOnstring = " Hi, how are doing?"

   if( searchText == 'ho'){
     // Output: false
   }

   if( searchText == 'How'){
     // Output: true
   }

@ComFreek Lol, I'd say about 80% of the 11 answers are `indexOf` :/ — tckmn, Sep 11 '13 at 12:11
possible duplicate of [whole word match in javascript](http://stackoverflow.com/questions/2232934/whole-word-match-in-javascript) — Felix Kling, Sep 11 '13 at 12:12
@Doorknob The most downvotes I've ever given to answers of a single question. Very sad. — ComFreek, Sep 11 '13 at 12:13
@ComFreek Haha, I'm going to favorite this *just* for the deleted answers :D — tckmn, Sep 11 '13 at 12:15
@Doorknob Me, too, for the future time when I will have 10k Rep :D /zermks: You gave me an upvote, didn't you? -.- — ComFreek, Sep 11 '13 at 12:17
@duffymo the last guy I heard saying something similar is missing now for 7 years already... :( — pandita, Sep 11 '13 at 12:28
@pandita I recommend you playing this game: http://regexcrossword.com/ ;) — ComFreek, Sep 11 '13 at 12:31
@ComFreek there is something seriously wrong with this... but it's intriguing in a way at the same time. Maybe it really is not that hard... Maybe I just have a quick go at it! — pandita, Sep 11 '13 at 12:58
@pandita It's not that hard as you may think at the beginning ;) If you need help, try [this bookmarklet](https://github.com/ComFreek/regex-cw-helper) (disclaimer: I'm the author). — ComFreek, Sep 11 '13 at 13:00
@ComFreek hehe I was trying to be funny but will certainly check this out — pandita, Sep 11 '13 at 13:07
@duffymo I just discovered that you used to do what I'm doing at the moment. Would you mind me asking you some questions outside of SO? — pandita, Sep 11 '13 at 13:10
No it's more about how you transitioned from mech to IT. I'm working on buildings/architecture atm. How did you jump? pandita.revolution@gmail.com — pandita, Sep 11 '13 at 14:31

score 21 · Accepted Answer · edited Feb 08 '22 at 13:43

21

You could use regular expressions:

\bhow\b

Example:

/\bhow\b/i.test(searchOnstring);

If you want to have a variable word (e.g. from a user input), you have to pay attention to not include special RegExp characters.

You have to escape them, for example with the function provided in the MDN _{(scroll down a bit)}:

function escapeRegExp(string){
  return string.replace(/([.*+?^=!:${}()|\[\]\/\\])/g, "\\$1");
}

var regex = '\\b';
regex += escapeRegExp(yourDynamicString);
regex += '\\b';

new RegExp(regex, "i").test(searchOnstring);

edited Feb 08 '22 at 13:43

Peter Mortensen

30,738
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answered Sep 11 '13 at 12:06

ComFreek

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it shows error like: Uncaught TypeError: Object function RegExp() { [native code] } has no method 'escape' – Anand Jha Sep 11 '13 at 12:25
@anand4tech You have to include that function before calling my code. /Thanks Doorknob. – ComFreek Sep 11 '13 at 12:28
This escape function is directly taken from https://developer.mozilla.org/en/docs/Web/JavaScript/Guide/Regular_Expressions – Denys Séguret Sep 11 '13 at 12:28
@anand4tech See my edit, I used the escape function from MDN, now. /dystroy: Thanks. – ComFreek Sep 11 '13 at 12:31
@ComFreek, The value of ---new RegExp(regex, "i").test(searchOnstring);--- is coming is always false – Anand Jha Sep 11 '13 at 12:40
function escapeRegExp(string){ return string.replace(/([.*+?^=!:${}()|\[\]\/\\])/g, "\\$1"); } function myFunction() { var yourDynamicString='how Are you'; var searchOnstring='how'; var regex = '\b'; regex += escapeRegExp(yourDynamicString); regex += '\b'; alert(regex) var y= new RegExp(regex, 'i').test(searchOnstring); alert(y) } – Anand Jha Sep 11 '13 at 12:41
@anand4tech 1. You confused *yourDynamicString* with *searchOnstring*. 2. One must escape '\' even in single quotes (my fault, sorry). 3. Please use semicolons. Working example: http://jsfiddle.net/Ydr3R/ – ComFreek Sep 11 '13 at 12:51
Is the example valid JavaScript code (not a rhetorical question)? – Peter Mortensen Feb 08 '22 at 13:49
@PeterMortensen Which example do you mean exactly? Can you give me a hint on what should be invalid syntax? (I wrote this answer 9 years ago :)) – ComFreek Feb 11 '22 at 13:05

score 3 · Answer 2 · edited May 23 '17 at 12:25

3

Here is a function that returns true with searchText is contained within searchOnString, ignoring case:

function isMatch(searchOnString, searchText) {
  searchText = searchText.replace(/[-\/\\^$*+?.()|[\]{}]/g, '\\$&');
  return searchOnString.match(new RegExp("\\b"+searchText+"\\b", "i")) != null;
}

Update, as mentioned you should escape the input, I'm using the escape function from https://stackoverflow.com/a/3561711/241294.

edited May 23 '17 at 12:25

Community

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1

answered Sep 11 '13 at 12:08

poida

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26
26

This is a link-only answer, which is discouraged. What happens if the link breaks? Your answer becomes useless. Also, we don't want people having to click *yet another* link after they arrive at SO. -1 – tckmn Sep 11 '13 at 12:14
@poida You should escape the `searchText`. – ComFreek Sep 11 '13 at 12:23
Now it's just wrong. And why are you checking for `null` anyway? – tckmn Sep 11 '13 at 12:23
Did you try it? (better now because of escape. -1 removed) – tckmn Sep 11 '13 at 12:51
@poida Removed my downvote, too, but one should really move the escape replacing into a function (I know, this is rather stylistic). – ComFreek Sep 11 '13 at 13:10

score -2 · Answer 3 · answered Sep 11 '13 at 12:09

-2

Something like this will work:

if(/\show\s/i.test(searchOnstring)){
    alert("Found how");
}

Search for a whole word in a string

4 Answers4

Linked