Chris Boesing Chris Boesing - 4 months ago 22
Javascript Question

JavaScript: case-insensitive search

I'm trying to get a case-insensitive search with two strings in JavaScript working.

Normally it would be like this:

var string="Stackoverflow is the BEST";
var result= string.search(/best/i);
alert(result);


The
/i
flag would be for case-insensitive.

But I need to search for a second string; without the flag it works perfect:

var string="Stackoverflow is the BEST";
var searchstring="best";
var result= string.search(searchstring);
alert(result);


If I add the
/i
flag to the above example it would search for searchstring and not for what is in the variable "searchstring" (next example not working):

var string="Stackoverflow is the BEST";
var searchstring="best";
var result= string.search(/searchstring/i);
alert(result);


How can I achieve this?

Dan Dan
Answer

Yeah, use .match, rather than .search. The result from the .match call will return the actual string that was matched itself, but it can still be used as a boolean value.

var string = "Stackoverflow is the BEST";
var result = string.match(/best/i);
// result == 'BEST';

if (result){
    alert('Matched');
}

Using a regular expression like that is probably the tidiest and most obvious way to do that in JavaScript, but bear in mind it is a regular expression, and thus can contain regex metacharacters. If you want to take the string from elsewhere (eg, user input), or if you want to avoid having to escape a lot of metacharacters, then you're probably best using indexOf like this:

matchString = 'best';
// If the match string is coming from user input you could do
// matchString = userInput.toLowerCase() here.

if (string.toLowerCase().indexOf(matchString) != -1){
    alert('Matched');
}
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