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I have seen numerous answers that say it’s just a matter of style, which is good practice due to Hoisting, but I wanted to know numbers (I don’t know how to get them) on the performance aspect. There is a performance difference amid:
var
fruta = 'banana',
pessoa = 'Maria',
acao = 'comer';
and
var fruta = 'banana';
var pessoa = 'Maria';
var acao = 'comer';
If there is a difference... does it keep using const and Let? If anyone can help me, I’d really appreciate it.
Doing a quick test (here and here) the difference seems insignificant to me. I would worry about the other aspects of
var
vslet
, as scope, Hoisting, etc., because performance does not seem to be the problem in this case. And if the app is having performance issues, probably the bottleneck isn’t there...– hkotsubo
wow, I didn’t know this benchmark site! Thanks! 15% slower didn’t seem like something so insignificant. Yes, in an application with few variables, this may not make much difference, but in a heavy application where each improvement makes a difference, I think it’s something else to consider. Nice to see the difference between immediate assign and late assign too. Thank you so much! Show!
– Paulo Rogério da Silva
I think these tests depend on the browser, because I only had differences less than 10%. Still, it would only make a difference if the script ran a million times, I don’t think that should be the biggest concern...
– hkotsubo