fun fun function in last Monday’s
episode we explored the JavaScript
prototype a lot of comments on this
asking how does this relate to factory
functions and factory functions is a
video I made a couple of weeks ago so
we’re going to spend this episode
thinking about when to use a factory
function and when do we want to use a
prototype and it basically comes down to
your performance needs vector functions
are more flexible and they are easier to
reason about but if you need extreme
performance the prototype might be
something that you want to look at since
there will be of course you will be
lowering how how easy it is to reason
about your code and how flexible it is
we’re also going to look at what do we
mean by extreme performance and skits
I think the factory functions is a great
default choice factory functions are so
flexible they allow you to create
objects in any way you want including
private properties and all that good
stuff secondly I think that factory
functions are really easy to understand
because I used so few concepts a factory
function is just a normal function that
creates an object as long as somebody
understands closures they can read your
code and understand since the factory
function is just dealing with object
literals and closures this is not a lot
of moving parts factory functions
doesn’t use the this keyword which means
that you don’t have the issue of this
changing value depending on context
which means that you don’t have to do
any messing around with bind to keep
that in context factory functions very
simple robust flexible easy to reason
about prototypes have less of all those
things but prototypes have great
performance before we talk about that
though I want to show you this week’s
discovery that doesn’t have anything to
do with programming at all and from this
kingdom builder we were
we’re having a boardgame night this
weekend and this is just an amazing game
I really really liked it it made it’s
made by Donald X much amber brahbrah and
he is is the guy that designed the
Dominion card game if you’ve seen it I
found out about Kingdom Builder through
the amazing YouTube show a tabletop I
will read them which you should watch
anyway objects made with prototypes are
created slightly faster and they use
slightly less memory so if you find
yourself in a situation where you need
to create tons and tons and tons of
objects it might be a good idea to
sacrifice the benefits of the factory
function and just go for creating
objects using the prototype instead but
when I say tons of objects I actually
mean tons of objects I actually don’t
mean that because they are non physical
objects living inside a computer and
don’t weigh anything let’s have a pop
quiz and evaluate what you have learned
so far if you are creating 10,000 items
per second should you use the prototype
or factory functions if you answered
prototypes you are wrong 10,000 items is
nothing we’re living in the future
computer is inside the cheapest mobile
phone and all the major JavaScript
engines are amazingly fast um I really
like this quote by Josh liebe vague or
often devs still approach performance of
Jay s code as if they are riding a horse
cart of the horse have long been
replaced with a fusion reactor now if
you have an app that creates 10,000
items per frame not for a second per
frame then you need prototypes then
we’re talking well maybe you need them
if you are creating 10,000 items break
in
you might indeed need to create objects
really fast but before you do you should
really ask yourself is the problem maybe
that I’m creating 10,000 items per frame
in the first place
the answer to that question might
actually be no you might need to create
that many objects but it is really
important that you attack the
performance characteristics of your
actual algorithm not nuances of it like
object creation that is a few thoughts
and when to use a prototype of when to
use a factory function Factory functions
are a little bit more robust it more
easy to reason about and more flexible
but if you need extreme performance
actually need it then the prototype is a
better choice it’s super important to
not search for the ultimate tool I know
I nag about this a lot on this channel
but it is really important Factory
functions and prototypes is such a great
example of a situation that you often
end up in as a programmer will you have
a a flexible tool that is very simple
and robust and you have a fast tool
which is not as flexible and robust and
it’s very important that you actually
only sacrifice the flexibility of this
tool if you actually need this speed
you’re going to need both of these tools
in your toolbox the flexible tool and
the fast tool but you should wait to
throw away your flexibility until you
know that you have to if you don’t know
about the performance characteristics of
your application go with the flexible
tool until you do if you try to predict
the future and say that yeah this this
part of my code that this is definitely
going to be slow I should use a fast
tool here if you do that you are not a
computer scientist you are you’re no
better than the person writing
horoscopes next to the funny pages use
the flexible tool until you find out
what parts of your app are actually slow
in real life and then and only then you
break out the master
I am mvj this is fun fun function until
next Monday morning stay curious you