const regex = /^0([1-9]{2})([1-9]{2})([2-3]{1})([0-9]{3})([0-9]{4})$|([1-9]{2})([8-9]{1})([0-9]{3})([0-9]{4})$/;
// Alternative syntax using RegExp constructor
// const regex = new RegExp('^0([1-9]{2})([1-9]{2})([2-3]{1})([0-9]{3})([0-9]{4})$|([1-9]{2})([8-9]{1})([0-9]{3})([0-9]{4})$', '')
const str = `7491260006`;
const subst = ``;
// 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