const regex = /\b([A-F0-9]{2})([A-F0-9]{2})([A-F0-9]{2})([A-F0-9]{2})-([A-F0-9]{2})([A-F0-9]{2})-([A-F0-9]{2})([A-F0-9]{2})-([A-F0-9]{2})([A-F0-9]{2})-([A-F0-9]{12})\b/gm;
// Alternative syntax using RegExp constructor
// const regex = new RegExp('\\b([A-F0-9]{2})([A-F0-9]{2})([A-F0-9]{2})([A-F0-9]{2})-([A-F0-9]{2})([A-F0-9]{2})-([A-F0-9]{2})([A-F0-9]{2})-([A-F0-9]{2})([A-F0-9]{2})-([A-F0-9]{12})\\b', 'gm')
const str = `f46279ee-aa28-497c-982c-403ac0ea84a6`;
const subst = `X'\4\3\2\1\6\5\8\7\9\10\11'`;
// 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