Question

I’d like a JavaScript regular expression that can match a string either at the start of another string, or after a hyphen in the string.

For example, “milne” and “lee” and “lees” should all match “Lees-Milne”.

This is my code so far:

var name = "Lees-Milne";
var text = "lee";

// I don't know what 'text' is ahead of time, so 
// best to use RegExp constructor.
var re = RegExp("^" + text | "-" + text, "i");

alert(re.exec(name.toLowerCase()));

However, this returns null. What am I doing wrong?

Answer 1

You could also use:

var re = RegExp("(?:^|-)" + text, "i");

Don’t forget to escape regex meta characters in text if it’s not an expression it self.

JavaScript has no built in function for that, but you could use:

function quotemeta(str){
    return str.replace(/[.+*?|\\^$(){}\[\]-]/g, '\\$&');
}