what it is why it exists and how to use
it if you are new to the channel welcome
I am your host npj and you are watching
fun fun function first of all what is
object dot create object create is a
static method on the object prototype
that creates a new object with the
prototype set to a certain object but
that’s a very long explanation and even
though I wrote it and I read it I got
bored half way and so now let’s instead
have a look at what it does let’s say
that we are writing an enterprise-grade
application and we have a normal object
that exists in such applications such as
let’s run that I know I’m calling this
file object trait sample j s and it says
new you’re aware that cat is sick that
is fine but we bought multiple types of
cats in our application that sounds
alright I’m gonna run that no the dart
object sample dodge it and you’ve I’m
let’s run that no dot object example
cats cats cats cats let’s walk through
this so we’re creating a simple object
here this is nothing special or
wonderful about this object it’s just an
object mineral with a with a method or a
property that we set to a function which
is fights then we can call it a method
and the console dot log it logs out the
properties sound on whatever this is
down here we call make sound so that
means it will go into this and it’s
gonna come to this line here
and it’s going to pick out whatever
sound is and we have set sound here on
this line we’ll set in the sound of mark
to move and that is why it logs out
sound if the concept of this confuses
you you might want to check out the
previous episodes in this series on
object creation in JavaScript you can
find a playlist with all the episodes in
in the description of this video so
check that out
if you watch the series you should be
familiar with everything up to this
point what you don’t know is what this
does what is this what is happening
inside of object of great what kind of
sorcery does this do object or create
creates a new object with the prototype
set to certain object so this object out
create will create a completely new
fresh object and it will set the
prototype of that object to be cat let’s
verify that I’m going to bright console
dot log is
smart a cat then I’m going to do this
I’m going to call Mark don’t is
prototype of cat I’m gonna run that node
dot object RIT Sambo J s force I did not
expect that
oh okay it’s because I’m I’m thinking in
backwards land so this does not make
sense I’m asking if Mark is a prototype
of the cat which it mark isn’t it’s the
cat that is the prototype of mark mark
is being derived or copied or whatever
you like to however you like to think
from the cat so it should be cat is a
prototype of of Mark is cat the
prototype of Mark and now I run that
again and you see that is Mark a cat
well true I accidentally said there
before that mark and and waffles or
copies of the cat which is not not true
that’s an incorrect way of thinking
about it what waffles and Mark are is a
new objects that don’t have the property
make sound themselves but they have a
reference to a prototype a cat and
whenever we ask for something like make
sound that does not exist on waffles and
mark themselves they delegate that call
to their prototype and ask the prototype
do you have the method make sound and if
so call that in a little bit we’re going
to look at how to use object.create but
first I want to talk about why object or
create exists in the first place what’s
the purpose of this thing well object
object is more natural to the prototype
model than the new keyword so in
previous episodes we looked at
how to apply the new keyword to a
function in order to simulate something
that looked sort of like classes and
that way was for a long time there the
factor or the the standard way of
creating objects in JavaScript it was a
kind of sort of class the problem was
that it it kind of looked like a class
but it looked really weird and it had a
bunch of quirks that just didn’t really
make sense from the standpoint of what
you expected of a class so Douglas
Crockford which you might know for being
the author of JavaScript good parts he
also did jslint you can think of Douglas
Crockford as the grumpy grandfather of
JavaScript and we was annoyed with the
state of object creation in JavaScript
so he wrote object creates as an attempt
to make something that was more in line
with how the prototype worked like
something that made a little more sense
and didn’t try to pretend being
something that it’s not you know a class
and Uggla’s Crockford being a person
that has a significant influence on the
JavaScript community managed to get
object create into the language itself
so object or create is built into
JavaScript even though it wasn’t at
first the more inquisitive student might
notice that we have been setting the
prototype directly in earlier episodes
we have us created objects and then to
stop just setting the prototype why why
introduce object create why doesn’t that
just make things more complicated and
yes it does object or create jumbles
together the creation and the of the
object and setting of the prototype but
a set prototype of and
messing with the prototype directly on
existing objects is a very bad idea from
a performance standpoint it makes it
very hard for the JavaScript engine to
optimize the speed of your application
which defeats the purpose of using the
prototype in the first place so in real
life we never use set prototype Alban we
never assign new prototypes to object
like we did in previous episodes set
prototype office very nice when
explaining the concept of a prototype
but in a real life application you
should not be using it you should be
using object or create which brings us
to how to use object.create but before
we do I’m going to take a walk and a
in the last week I’ve gotten a bit
addicted to the video Q&A app wale I’ve
been answering a lot of questions away
up this morning I answered this one by
Tong Qi how do you handle ideas about
the things that you can solve with your
programming skills and what stops you
from turning said solution into a
business man this question hits close to
home
for me this is a huge problem for me I
have like a million ideas all the time
and being a programmer you see that oh I
could solve this problem with software
so easily and it would benefit so many
people if if there just was a piece of
software that’s all this ah and this
line of thinking has caused me to start
each Li 30 projects but I stopped myself
from doing that nowadays because those
projects never amount to anything
the reason these projects are almost
never amount to anything
is that launching a software product is
not just coding it it is building a
business around it creating business
model investing in that business
launching that product marketing that
product and then over time maintaining
and and running that business building
the software is a tiny tiny bit of all
that work so now whenever I think of
this awesome software idea that would
change the life of a couple people and
it would be real great I asked myself
hmm am I really willing to spend the
next one or two years of my life
focusing on focusing on this thing
because that is honestly what it would
take to
to make it happen and usually not is not
a case it’s the ideas are often not that
way I really don’t like when people say
that oh I have so little time time is
the only thing that we have in abundance
like it’s this huge resource of of ours
that gets replenished every single day
so if you have that feeling that oh
there’s so little time and so busy then
the problem is not really the amount of
time that you have you have vast amounts
of it the problem is how you spend the
time in case you’re new to this channel
I live in Sweden and I’m also
stereotypically close to IKEA or Kia
beset in Swedish and this is where I’m
going to eat lunch because it’s lunch is
all right we’re back how to use
object.create we’re back to the example
that we had before I’m going to clear
the console a great way to understand
tools you know libraries or built-in
functions is to use try to really
implement them so that is what we’re
going to do first we’re going to create
object or create them we’re gonna call
okay so what arguments does our object
rate function take well it takes a
prototype let’s just call that proto
because I think that a prototype is
probably a reserved keyword I don’t know
but I’m guessing object.create
actually takes a second object second
argument that is a properties object we
are not going to deal with that today
it’s not really related to how object
treats works and you don’t need it to
understand this and I honestly don’t
think you need it period the first thing
that object not create does internally
is to create an object here’s a simple
object and then it’s going to set the
prototype of that object we use the set
prototype of and we’re going to set the
prototype of the object to our proto and
then we’re going to return the object
let us run that node object for example
ah keep forgetting the test
yes and it still gives the same output
as before so if we take a look here at
object create like what this does so
check this out
create a new object here create a new
object and it then sets the prototype of
that object to a certain object which in
this case is is is proto that’s it
that’s the gist of what object create
dots but we’re not going to use the set
prototype all because that is a horrible
from a performance standpoint and
performance is again why we’re using the
prototype in the first place
so we’re going to do object create here
yes
when using object or create in real life
you like this seems this this
implementation might seem wrong to a lot
of people and that is because it is if
this was a class there
in initialization here this would
probably be part of some constructor if
this was a real object there would
probably be a lot more functionality and
setup that goes on here
probably some conditionals and some
checks for that you’ve set all the cat
Anatomy so where do you put constructor
logic because object doc object create
there is no space for a constructor and
the most common pattern is to simply
just use an init function like init
letter that the third function and just
like a constructor you would here
provide the data that is needed to
construct the cat for instance sound and
then you’d go set this don’t sound
equals sound I know this is a contrived
example you have to imagine that the
init function actually contains more
logic I forgot a comma there and now
we’ll replace this sound assignment here
with in its name
num there and the same thing down here
in it fruit rook we’ve run that again to
make sure that it works as before yes we
get the same output a Halle pattern here
is to just return this because then you
can chain these calls and do object
traded cat maybe a delete here the law
do the same thing here I’ll just bunk
bunk bunk a new line and I run that
again same output and that is it object
not create is a very simple
straightforward way to create objects
that use prototypes object or create
it’s nice it has great CPU and memory
characteristics and as long as you
understand how what the prototype is
this is a very straightforward
nice pattern if anything was confusing
please post a question down in the
comments if it wasn’t confusing please
help out the person that has posted that
question in the comments you have just
watched an episode of fun fun function
if you’re new welcome this is a
programming show and I post new episodes
every Monday morning Oh 800 GMT you have
just watched an episode that was a bit
tutorial like but I also do these other
musings episodes where I’m there are
more thought pieces where I talk about
architecture working in a team
productivity and stuff like that you can
check that out in this playlist
I am mvj until next Monday morning stay curious