how to convet date into unix string in js code example

Example 1: unix time to date javascript

const unixTime = 1210981217;
const date = new Date(unixTime*1000);
console.log(date.toLocaleDateString("en-US"));
//expected: "5/16/2008"

Example 2: javascript date convert to unix

new Date('2012.08.10').getTime() / 1000