Convert JS date time to MySQL datetime

I think the solution can be less clunky by using method toISOString(), it has a wide browser compatibility.

So your expression will be a one-liner:

new Date().toISOString().slice(0, 19).replace('T', ' ');

The generated output:

"2017-06-29 17:54:04"

var date;
date = new Date();
date = date.getUTCFullYear() + '-' +
    ('00' + (date.getUTCMonth()+1)).slice(-2) + '-' +
    ('00' + date.getUTCDate()).slice(-2) + ' ' + 
    ('00' + date.getUTCHours()).slice(-2) + ':' + 
    ('00' + date.getUTCMinutes()).slice(-2) + ':' + 
    ('00' + date.getUTCSeconds()).slice(-2);
console.log(date);

or even shorter:

new Date().toISOString().slice(0, 19).replace('T', ' ');

Output:

2012-06-22 05:40:06

For more advanced use cases, including controlling the timezone, consider using http://momentjs.com/:

require('moment')().format('YYYY-MM-DD HH:mm:ss');

For a lightweight alternative to momentjs, consider https://github.com/taylorhakes/fecha

require('fecha').format('YYYY-MM-DD HH:mm:ss')