Extraction of string using regex in javascript

Question

I have a string of the following format:

"hello(%npm%)hi"

My goal is to split the string into three parts

a) hello
b) (%npm%)
c) hi

I am using regex as follows:

var myString = "hello(%npm%)hi".match(/[a-z]*/);
        var backdtring  = "hello(%npm%)hi".match(/\)[a-z]*/);
        var midstring  = "hello(%npm%)hi".match(/\(\%[a-z]*\%\)/);

var res = backdtring.replace(")", "");

https://jsfiddle.net/1988/ff6aupmL/

I am trying in jsfiddle , where theres an error in the line:

var res = backdtring.replace(")", "");

"backdtring.replace is not a function" .

Whats wrong in the replace function above?

Update: Also, have I used the best practices of regular expressions ?

Answer 1

As it has been mentioned in the comments, you are trying to use a String#replace method on an array, see the description of the return value of String#match:

An Array containing the entire match result and any parentheses-captured matched results; null if there were no matches.

To streamline tokenization, I'd rather use .split(/(\([^()]*\))/) to get all substrings in parentheses and the substrings that remain:

var s = "hello(%npm%)hi";
var res = s.split(/(\([^()]*\))/);
console.log(res);

Details:

• (\([^()]*\)) - the pattern is enclosed with capturing group so as split could return both the substrings that match and those that do not match the pattern
• \( -a literal (
• [^()]* - 0+ chars other than ( and )
• \) - a literal ).