Node.js Tutorial for Beginners - 5 - Understanding References to Objects Video Lecture | The Complete NodeJS Developer Course - Back-End Programming

are already hostas in this video what
I'm going to do is I'm going to clear up
some concepts that you're going to come
across a lot in nodejs
development the first thing is you're
probably going to hear if you haven't
already that in node everything is a
reference what does that mean well check
this out say that we have an object
called Bucky and I'm just going to make
two quick properties I'll say like fav
food I'll type anything bacon and fav
movie I will say by the way I saw this
last night the movie chappie if you
haven't seen it I highly recommend it it
is actually a pretty funny movie and
entertaining and actually the
programming in it is a not completely
unrealistic you know and so movies are
like oh can we hack into Microsoft's
JPEGs and track the IP you know it's
actually a lot better than all right
back to uh the tutorials I talked to
Maya
alright so whenever you're working with
node everything is a reference what that
means is if you were to make a new
variable called person and set this
equal to Bucky you may be thinking okay
so what I'm doing is I'm taking all of
this making a copy of it and now person
is pretty much a new object so what I
can do here is I can take person which
is this new person and set their
favorite food equal to salad something
like that so of course
Bucky's favorite food would still be
bacon and the new person's favorite food
would be salad simple enough right well
check this out if we take console and
print out Bucky dot fav food look what
happens you run this it says salad wait
a minute
I set Bucky's favorite food to bacon and
just this new person I made a copy of
Bucky but then I changed their favorite
food to salad so why did it change
Bucky's to salad well this is what's a
little bit different and may trick you
up a little bit in the future whenever
you assign Bucky to person right
here you're not making a copy of all the
properties in everything inside this
object you're just getting a reference
to Bucky so whenever you type person you
can pretty much think of it like that so
again whenever you change person
favorite food since person is a
reference to Bucky you're actually
changing Bucky's or my favorite food so
that's what's going to trick a lot of
people up and if you actually want to
make a copy of this and you know try to
make this program like you expected I'm
going to show you guys how to do that in
a couple tutorials the proper way of
making multiple copies of objects but
that's what people mean whenever they
say everything is a reference now
another thing I want to explain is this
what is the difference between two equal
signs and three equal signs and this is
actually a really popular interview
question so let's just take console I'll
explain it really really easily so
whenever you use two equal signs such as
you're comparing the number 19 to the
string 19 what's going to happen is this
is going to print out true so even
though that this is a number and this is
a string whenever you use two equal
signs
it only compares the values so again the
number is equal to 19 the string
holy-moly let the copy that not undo
everything all right now check this out
whenever you use three equal signs this
is going to log out false so the
difference between two equal signs and
three equal signs is this two equal
signs use whenever you only want to
compare values three equal signs use
whenever you want to compare values and
types so sentence nineteen is equal to
19 but there are different types this is
a string and this is an integer it's
going to log out false so popular
interview question do not forget that
one let me clean up everything alright
now since I have a little bit of time
the last thing I want to explain
actually I'm gonna explain this in the
next tutorial by the way what I'm going
to explain is this the keyword this so
uh I thought that was kind of funny but
whatever I'll see you then