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To develop complex scripts, or even just a large library of scripts using Selenium Webdriver, eventually a more abstract way of approaching the interface between the script and the page will be needed. In this video we will take a look at page models and how this design pattern can help us create scripts that are easier to create, maintain, and understand.
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Other Languages Handling of Locators
In many languages, you would store locators as a static property. These are sometimes returned to as class properties or class level fields.
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The functions that we created to add and
0:00
remove invitees do a great job of
having us not repeat ourselves in code.
0:02
Meaning we don't need to write code
to find the form, fill it out, and
0:07
then click the Submit button over and
over.
0:11
We just call the function and
pass it a name.
0:14
It also provides another benefit,
0:17
it abstracts away the need to know what
is actually required to add an invitee.
0:19
As a user of this function, i don't
need to know how the invitee is added,
0:25
I just know it happens.
0:29
This way of thinking should feel
pretty familiar if you've done any
0:32
object oriented programming, or OOP.
0:35
Where you keep hidden or encapsulate the
information that you don't want your users
0:37
to worry about, and
you expose what you want them to use.
0:42
Well users of our automation code should
have that same sort of respect and care.
0:46
We should be able to say, this is the
homepage, and you can add invitees, and
0:51
remove them.
0:55
Don't worry how it's done, I got this.
0:56
Now, over time, best practices have
evolved on how to do this, and
0:58
a pattern has emerged,
it's called the Page Object Model.
1:01
Now note the word there,
object, the first O in OOP.
1:05
So languages have different
ways of doing OOP.
1:11
And while we're doing this in JavaScript,
1:14
you can imagine this extended to whatever
programming language your code base is in.
1:16
So what do you say we go about
creating our first page object?
1:20
Okay, so
we have a pretty good start here already.
1:25
And the way that we built this
code up is actually pretty common.
1:28
First you work on your selectors,
next you work on your abstractions.
1:31
So what we wanna do now is build a new
place to store page-specific information.
1:35
So in JavaScript land,
we'll make a module.
1:41
Now this is equivalent to packages or
namespaces in other languages.
1:44
So what I'll do is I'll come over here
,and I'm gonna make a new folder,
1:47
and I'm gonna call that pages.
1:52
And I'll add a new file to this folder,
and
1:55
I'm gonna call it home.js.
2:00
Our app only has one page, and
it's typical to name your main page home.
2:03
Okay, so
you might not have seen this before, but
2:09
in the later version of JavaScript,
they introduced a new class keyword.
2:12
It's syntactic sugar for
how you build objects in JavaScript.
2:16
I'm gonna use it here because it's
the most language agnostic way to get
2:20
the point across.
2:23
Please don't let it trip you up,
more information on the teacher's notes.
2:25
So we are gonna create
a class called HomePage,
2:28
and we'll add a constructor
method to our class.
2:31
Now, this is method that's called when
the new object is created or constructed.
2:35
So it's common to pass the web driver into
the page object, so I'll say constructor.
2:40
And that's how you do this in JavaScript,
it's called constructor, and
2:45
then this is what is expected.
2:48
And then now I can use this, right?
2:50
So we'll store a reference to
the driver in our instance.
2:52
Okay, and
2:59
now let's explicitly state that this is
the class that we wanna have exported.
3:00
So the way that you do that in
Node is you say, nodule.exports,
3:05
and we're gonna say HomePage.
3:10
So this is specifically saying hey, if you
import this file, you can export HomePage.
3:12
So now, let's go import it,
so in our index file,
3:18
we'll come over here and
we'll say const HomePage = require,
3:23
So in the current directory, pages/home.
3:31
Cool, so now we have it, right?
3:35
So now we have the ability to create one
of these, so that's our class definition.
3:37
And then after we build our driver here,
3:41
what we'll do is we'll pass
it into our HomePage object.
3:44
So we'll make a lower case
of homePage here, right?
3:47
So we're gonna make an instance
of that page, HomePage,
3:50
and we're gonna pass in driver.
3:53
Now we move page-specific stuff
from index js into our page.
3:56
So it's a common approach that your page
understands how to navigate to itself.
4:01
So let's do this, let's cut this
driver.get, we'll cut that from this file.
4:06
And we'll come over here
into the HomePage, and
4:13
what we'll do is we'll make
a new method called open, okay?
4:14
And in here, we will paste our code.
4:20
Now, normally you wouldn't have
to use the dynamic process.env,
4:25
right, URL from the command line, but
that is because ours is dynamic, and
4:30
I want this code to work for everybody.
4:33
So the thing that we need to remember
is that we need to use this.driver.
4:35
Cool, so now we have a method that
we can call on our instance, so
4:40
we can say homePage.open().
4:44
And see, it knew about it there,
pretty neat, right?
4:47
Okay, so let's keep these invitees here.
4:50
I'm gonna collapse this,
invitees, there we go.
4:53
Now, this doesn't really belong here,
does it?
4:56
If we take this locators out,
this really belongs in the page object.
4:58
So I'm gonna cut, and
I'm gonna come over to my page object,
5:03
and I am going to paste
in the constructor,
5:09
paste in here, this.locators.
5:13
Cuz I wanted to be
a property of this class.
5:17
Now different languages handle
this a little bit differently, so
5:20
check the teacher's notes for
more information.
5:23
Go head and semicolon there, okay and
check this out, we're using this By, so
5:26
we need to do our imports over here.
5:31
So let's go ahead and let's bring in
5:33
let's bring in this, both of these.
5:37
Or actually, what we could do is we could
just say, let's do this a little proper.
5:42
That's one way of getting very specific
about what it is that you need.
5:48
So we just need the By, so we'll say
By = require("selenium-webdriver").By,
5:53
there you go.
5:58
And we don't have to bring in Selenium
over there, cuz we're not using it,
6:00
it's not in the namespace.
6:03
Okay, so back in index.js, let's grab our
functions that don't belong here anymore.
6:05
So I'm gonna grab the function, the
removeInvitee and the toggle right here.
6:11
So I'm gonna grab all these functions,
and I'm gonna cut them out, and
6:17
I'm gonna come over to my home.js.
6:21
I'm gonna come down in here, let's get
this up here a bit, and I'm gonna paste.
6:25
And you'll see the squiggle,
6:31
says that the function doesn't
belong here inside of a class.
6:32
So I need to get rid of all those.
6:35
So what I'm gonna do is I'm gonna
use the multiple cursor shortcut
6:38
in Visual Studio Code.
6:41
And it's kind of one of those killer
features that when you need it,
6:42
it's exactly what you need.
6:46
Here, check this out, so
I'm gonna turn on a little key tracker so
6:48
you can see what I'm doing here.
6:51
So I'm gonna turn this on, and I'm just
gonna press Cmd+D, and I get all of them.
6:53
And I see there's a cursor
on each one of them.
6:59
I'm gonna select the word function
up until the function there, and
7:02
then I'm gonna delete it, bam.
7:07
And then I'm gonna press Escape
to get rid of it, there we go.
7:10
And now we're back to a single cursor, but
I'm gonna move over here and I'm gonna get
7:13
each one of these drivers, because the
driver needs to access this driver, right?
7:17
So I'm gonna highlight this one,
get all of them.
7:22
I'm gonna go to the front,
I'm gonna type this dot, and press Escape.
7:26
We have the same problem with
these locators, don't we?
7:32
So I'm gonna go here, and
I'm gonna do locators,
7:34
get all those locators, jump over
to the front, and do this.locators.
7:38
Wow, let's take a moment and just
appreciate how amazing that feature is.
7:43
Okay, now let's flip back the index.
7:49
[LAUGH] This is looking pretty great,
isn't it?
7:51
So this is our whole file now,
7:54
we've got the home page here,
it can fit on one screen.
7:57
So let's do this,
first things that we need to do
7:59
is we need to change the calls
to use them currently, right?
8:03
So, let's see, let's flip this back
really quick, so it's more clear.
8:05
So forEach invitee we want to
call homePage.addInvitee and
8:08
then pass in the invitee.
8:16
And just a little
JavaScript free hint here,
8:19
you can still do what we were doing before
where we just passed in the method right?
8:21
So we could just say homePage.addInvitee.
8:26
But the problem is that when
it calls this function,
8:29
it doesn't know what this should be.
8:33
So that's what the second
parameter here is,
8:35
it's called thisArg, see that up there?
8:37
So it needs to know what this is, and
8:40
this in the case is homePage, here we go.
8:43
All right, and before this Shadd call,
8:48
what we wanna do is call homePage,
we'll call that method.
8:51
And we also wanna do that for
our toggle, so we can say,
8:57
homePage.toggle, awesome.
9:01
Wow, this looks great right?
9:08
Not many lines at all.
9:09
So let's go ahead and give this a run.
9:11
I'm gonna close this existing one,
let's give that a run.
9:14
Make sure everything's still working,
sure looks like it is.
9:22
Okay, so
let's say that we wanted to click this
9:26
Confirmed check box here for
a specific invitee.
9:31
Hm, we already have one for
our remove invitee function, but
9:36
that's not exactly great, isn't it?
9:41
It means we'd have to build a function for
each one of those new,
9:44
parse the invitee and each time for that.
9:48
I don't really wanna do that for
9:50
each of this interactions
that the invitees can do.
9:51
So now that these things are in classes,
we could probably do a better job of
9:54
returning an invitee and
modeling that as a page object model.
9:58
Common misconception of this
page object pattern is that you
10:03
need to make a page object
the entire page only.
10:05
But you can for sure make them a part of
the page only, a sub page, if you will.
10:08
Now this ends up feeling
a lot like web components.
10:13
So let's do this, you're doing great,
you're cruising through this content.
10:15
Why don't you take a quick break,
do some stretching or jumping jacks, and
10:18
get the brain juice flowing.
10:22
And then come back and
we'll build the page object just for
10:23
this little invitee thing here.
10:26
Sound good?
10:30
See you in a bit
10:31
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