const regex = /\}\}\}(.*)/g;
// Alternative syntax using RegExp constructor
// const regex = new RegExp('\\}\\}\\}(.*)', 'g')
const str = `{"body":{"records": {"time": "2020-12-20T13:28:50.2164144Z","MachineGroup": "Windows 10", "Timestamp": "2020-12-20T13:27:18.6679858Z", "DeviceName": "3242d4e4.dc.democorp.com", "ReportId": 306737}}},"x-opt-sequence-number":159959006,"x-opt-offset":"2713650553292728","x-opt-enqueued-time":1624195823422}`;
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