js convert dd/mm/yyyy to yyyy-mm-dd code example

Example 1: javascript convert date to yyyy-mm-dd

// `date` is a `Date` object
const formatYmd = date => date.toISOString().slice(0, 10);

// Example
formatYmd(new Date());      // 2020-05-06

Example 2: javascript convert date from mm/dd/yyyy to yyyymmdd

var yourdate = date.split("/").reverse().join("-");