both are correct and both will work
read the doc for debounce here... his method may be technically better because you are not needing to wrap the callback in an arrow function.. but both will work and you wouldn't notice any difference in practical terms.
EDIT: having looked more closely at the doc.. here is the method signature for debounce
debounce (target, method, args*, wait, immediate)
Optional arguments to pass to the timeout.
args should be an
Object... I'm a little confused by this... I would expect it to be an array.. I haven't tried this and so I'm not familiar with passing the args object here..
I have only used the method I originally posted.. and I know that way works as intended..