const regex = /((\w+)\.(\w+) as \3(\d_\d)_)(, \2\.\w+ as \w+)*/g;
// Alternative syntax using RegExp constructor
// const regex = new RegExp('((\\w+)\\.(\\w+) as \\3(\\d_\\d)_)(, \\2\\.\\w+ as \\w+)*', 'g')
const str = ``;
const subst = `$2.**$4`;
// The substituted value will be contained in the result variable
const result = str.replace(regex, subst);
console.log('Substitution result: ', result);
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for JavaScript, please visit: https://developer.mozilla.org/en/docs/Web/JavaScript/Guide/Regular_Expressions