regex-match-group.js

/**
 * Given we have a regex with one more matching groups. 
 * The regex should capture those groups from an 'input' 
 * string and replace the matched values in an 'template' 
 * string. 
 * 
 * Example:
 * regex: /([1-9]{8})/([1-9]{8})?/
 * input string: '/some-magic/path/12122211/22112211'
 * template string: 'http://someurl?adId=$1&adId=$2'
 * 
 * Should produce following output: 
 * http://someurl?adId=12122211&adId=22112211
 * 
 * My current implementation, kinda works, but would love
 * to improve the string-template updater. 
 */

const re = new RegExp('/([1-9]{8})/([1-9]{8})?');

const input = '/some-magic/path/12122211/22112211';

const template = 'http://someurl?adId=$1&adId=$2';

const match = re.exec(input);

let output = template;

if (match) {
    for(let i=1; i<match.length; i++) {
        if(match[i]) {
            output = output.replace(`$${i}`, match[i])
        }
    }
}

console.log(output);

Trygve almost there with template strings: https://gist.github.com/trygve-lie/4255138406b9b5969ce3c5da7a0711fb

@sveisvei got it: https://gist.github.com/sveisvei/8a495f2e2db41a768bb0bcd43e724bc4