Javascript pattern for test from input value

Question

What I want is simple. I have an input field and I want to check what items from an unordered list (ul) contain the input's value.

So, I have this:

$('input#search').keyup(
    function() {
        var value = $(this).val();
        if (value.length > 0) {
            var patt = /value/g;
            console.log(patt);
            $('ul#list li').filter(function() {
                return (patt.test($(this).html()));
            });
        }
     }
);

My problem here is that if, for example, the value of the input is 'abcd' patt will be /value/g instead of /abcd/g so I want to know how can I insert the value in the pattern.

wouldn't [`indexOf`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/indexOf) be a better fit? — Brad Christie, Jan 07 '14 at 13:57

score 0 · Answer 1 · answered Jan 07 '14 at 13:58

0

define patt as new RegExp

var patt = new RegExp(value,"g")

answered Jan 07 '14 at 13:58

Sergei Zahharenko

1,514
12
16

score 0 · Accepted Answer · edited May 23 '17 at 12:28

To create a pattern based on dynamic data you'd use the RegExp ctor passing it a string of the pattern. e.g.

var word = 'foo';
var re = new RegExp(word, 'g'); // var re = /foo/g

Don't forget to escape characters with special meaning in regexp.

However, if you're just looking for a simple "is x within y" comparison, indexOf can perform this check very quickly:

var sample = 'this is a foo sentence';
var loc = 'Hello, world!'.indexOf('world') // 7

then simply check if indexOf(...) != -1.

Javascript pattern for test from input value

2 Answers2