javascript syntax error: invalid regular expression

Question

I am writing an application in javascript. In my application there is an option to search for a string/regex. The problem is match returns javascript error if user types wro

Answer 1

Use a try-catch statement:

function myFunction() {
    var filter = $("#text_id").val();
    var query = "select * from table";
    try {
        var regex = new RegExp(filter);
    } catch(e) {
        alert(e);
        return false;
    }
    var found = regex.test(query);
}

Answer 2

Perhaps you should try escaping the slashes on a line before the "var query". If you want to search a string for a slash in regex, it must be escaped or regex will read it as a reserved character.

Answer 3

In this case you didn't actually need regular expressions, but if you want to avoid invalid characters in your expression you should escape it:

RegExp.quote = function(str) {
     return str.replace(/([.?*+^$[\]\\(){}|-])/g, "\\$1");
};

Usage:

var re = new RegExp(RegExp.quote(filter));

Without a regular expression you could have done this:

if (query.indexOf(filter) != -1) {
}