const regex = /"amount":"[\$]?([0-9]{1,3}),([0-9]{1,3})"/gm;
// Alternative syntax using RegExp constructor
// const regex = new RegExp('"amount":"[\\$]?([0-9]{1,3}),([0-9]{1,3})"', 'gm')
const str = `[{"team":"Green Bay Packers","active":"1","year_started":"2018","end_year":"2022","amount":"\$2,578,408","amount_guaranteed":"\$118,408"}]
[{"team":"San Diego Padres","active":"0","year_started":"2020","end_year":"2020","amount":"563,500","amount_guaranteed":""},{"team":"San Diego Padres","active":"0","year_started":"2019","end_year":"2019","amount":"555,000","amount_guaranteed":""}]
[{"team":"Washington Wizards","active":"1","year_started":"2019","end_year":"2021","amount":"\$12,000,000","amount_guaranteed":"\$12,000,000"},{"team":"Orlando Magic","active":"0","year_started":"2011","end_year":"2011","amount":"522,472","amount_guaranteed":""},{"team":"Orlando Magic","active":"0","year_started":"2012","end_year":"2013","amount":"2,854,389","amount_guaranteed":""},{"team":"Oklahoma City Thunder","active":"0","year_started":"2014","end_year":"2014","amount":"923,373","amount_guaranteed":""},{"team":"Houston Rockets","active":"0","year_started":"2014","end_year":"2014","amount":"981,084","amount_guaranteed":""},{"team":"Washington Wizards","active":"0","year_started":"2015","end_year":"2015","amount":"1,100,602","amount_guaranteed":""},{"team":"Detroit Pistons","active":"0","year_started":"2016","end_year":"2018","amount":"18,000,000","amount_guaranteed":""}]`;
const subst = `"amount":"$1$2",`;
// 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