Replace all chars with #, except for last 4

If you find the solution, try this trick

function maskify(cc) {
  return cc.slice(0, -4).replace(/./g, '#') + cc.slice(-4);
}

You could do it like this:

dd.replace(/.(?=.{4,}$)/g, '#');

var dd = 'Hello dude';
var replaced = dd.replace(/.(?=.{4,}$)/g, '#');
document.write(replaced);

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