RegexExp not capturing group properly

Question

I am trying to eliminate some characters if found in my string like v_[i] will be v.To do this I am using RegExp but it is not capturing the group.

var string='v_[i]';
var regexExp = new RegExp('_[\w+]','ig');
var finalstring = string.replace(regexExp,'');
alert(finalstring);

While in the other hand if i use a literal string it works perfectly

var finalstring = string.replace(/_\[\w+\]/ig,'');

then why RegExp not capturing the group as the literal string does.

Answer 1

You should escape the brackets in your regex:

var string = 'v_[i]';
var regexExp = /_\[\w+\]/ig;
var finalstring = string.replace(regexExp, '');