to talk about the optional chaining
operator in JavaScript
I am MP J’s and you are watching
[Music]
all right so what does this optional
chaining operator look like let’s have a
look at that first all right so we have
an object here called user which has one
property called name and that is
fluffykins and here we are a psych
rating variable called the zip code and
here we’re kind of trained access a
property that does not exist on the user
an address and then we in turn will try
to access an another property that does
not exist only non-existent object
called zip code so let’s say that we
have users that some of them have names
some of them also have addresses and if
we use the optional chaining operator
this means that zip code here would be
undefined and if we didn’t have this we
didn’t have this in choose that then
this code would actually immediately
break that’s me let me actually just
execute that start up our phone there we
go and you see that cannot read
properties set or undefined now you
might notice here that these go red and
that is because unless you’re watching
this from the future this does not exist
in JavaScript quite yet the optional
chaining operator is a proposal for
JavaScript it’s at stage 1 and there are
four stages however I do think that this
is likely to be implemented because it’s
an obviously useful feature it already
exists in c-sharp also you can use this
already today using battle and you can
find a link to how to do that in the
episode description unless you are
watching this from the future all right
so why does this exist what’s the point
of this all right so let’s think about
the problem here we have we need to
access
says the zip code of our users but the
problem is that some users don’t have an
address which means that we get these
cannot read properties zip of undefined
errors oh can I make an interesting
observation here this problem only
exists because in JavaScript and many
languages variables and properties can
be not or undefined or nil or whatever
you would like to call them they can be
like set to point to nothing and that is
what creates problems like this and
languages like rust for example thus
completely away with the concept of null
in order to avoid these kinds of
problems sure but javascript does have
this problem so we need to deal with it
somehow
all right um maybe we can solve it with
a logic expression fine that works but
like you see it’s it’s it’s very noisy
it’s it’s very verbose that’s true maybe
oh I think this is a great example of
why nested ternary operators or so hard
to read I just look at this and I just
feel the ulcer growing in my stomach hey
no problem let’s solve it with a
I think this is also very noisy it has
it also has his own scopes so we have to
do this weird mutable variable here we
can’t use Const anymore
also let’s delete this comment here we
don’t need that now that we’re using oh
I know what we could do please don’t
write a light I’ll write a library
ah that wasn’t too much code actually Oh
for the love oh end using recursion
always makes me feel so smart literally
thousands of years of developer time
must have been wasted on writing this
function fine I’ll use a third-party
all right now it’s such a nice library I
feel like it’s weird that the syntax
here is reversed from the function that
we wrote earlier like the properties
come first and they come as an array and
the second argument here is the the
object why why is it like that
oh the benefit of that is that it allows
us to carry it with Rhonda hang on I’ll
so you see here that we can reuse get
sip in multiple places in our app
because of their their the Korean fine
but wouldn’t it be cool if something
like Graham that part was built into the
okay so apart from the fact this does
not exist yet I think that this is a
really nice solution it’s a lot shorter
than all the other solution including
the little library that we wrote just to
solve this problem yeah but is it really
all that much shorter mmm it’s shorter
but we’re still talking about
introducing a whole new language feature
here if we add a new language feature
for every little thing that we want to
solve in JavaScript we we’re gonna end
up with a language that has a very steep
learning curve one of the nicest things
about javascript is that there are and
to manage language constructs to learn
is the optional chaining operator a
useful feature that is worth the
complexity it adds to the language or is
it just cuddling with these c-sharp
developers post a comment down below or
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here I am mvj until next Monday morning State