const regex = /\d{4}(.\d{2}){2}(\s|T)(\d{2}.){2}\d{2}/g;
// Alternative syntax using RegExp constructor
// const regex = new RegExp('\\d{4}(.\\d{2}){2}(\\s|T)(\\d{2}.){2}\\d{2}', 'g')
const str = `2015-09-18 07:41:10.878357
2015-09-18T07:41:10.878357
2015/09/18T07:41:10.878357`;
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