// Depending on timezone, your results will vary
const date = new Date('20 December 2019 14:48');

console.log(date[Symbol.toPrimitive]('string'));
// Expected output: "Fri Dec 20 2019 14:48:00 GMT+0530 (India Standard Time)"

console.log(date[Symbol.toPrimitive]('number'));
// Expected output: 1576833480000