Javascript: Wildcard regex search

Question

I need to filter an array of string with a wildcard regex:

// my search key
var myKeyword = 'bar';

// my search list
var strings = ['foo', 'bar', 'foobar', 'barfoo', 'hello', 'java', 'script', 'javascript'];

// my results
var results = [];

// the regexp, I don't understand
var regex = new RegExp(\*/, myKeyword);

// the for loop
for (var i = 0; i < strings.length; i++) {
    if (regex.test(strings[i]) {
        results.push(strings[i]);
    }
}

console.log(results); // prints ['bar', 'foobar', 'barfoo']

So how do I fix the regex?

Answer 1

If you want to do it with a regex, do it like this:

var regex = new RegExp(keyword);
// if you want it case-insensitive:
var regex = new RegExp(keyword, 'i');

This will break if the keyword contains any regex-specific characters such as [ or * . You need to write a function to escape these characters if that's a problem for you.

However, you can solve your problem much easier by using strings[i].indexOf(keyword) != -1 to test if the keyword is in the string or not - without using a regex at all.

Answer 2

Not too sure what exactly you're trying to do here. Javascript does have literal REs so you could just do:

var regex = /foo/;

which is just a nicer way of doing:

var regex = new RegExp( 'foo' );

(but in the second case, the 'foo' could be a string argument being passed in.

You don't need any leading/trailing wildcards on a regular expression.