Accepts two arguments: the length the string should be, and what characters to add if it’s not that length. The characters to use is optional, and defaults to a space ().
// Add a leading zero for hours below 10
var minutes0 = '0';
var minutes12 = '12';
// returns "00"
minutes0.padEnd(2, '0');
// returns "12"
minutes12.padEnd(2, '0');
Source
https://vanillajstoolkit.com/reference/strings/string-padend/