epoch date is generally in seconds and milliseconds.
sample: /Date(1665424800000)/
javascript code to convert in readable date:
var lsad = String(LoanSanctionApproveDate);
var lsadUnixDate = lsad.slice(6, 19);
var lsadToInt = parseInt(lsadUnixDate);
var loanSancAprvDate = new Date(lsadToInt).toLocaleDateString('es-CL');