1
00:00:00,120 --> 00:00:07,920
And before we cover more complicated use state examples, let me just cover some things that relate

2
00:00:07,920 --> 00:00:09,080
to all hooks.

3
00:00:09,330 --> 00:00:13,650
So this will also relate to all the other hooks we'll learn later.

4
00:00:13,890 --> 00:00:20,130
And first, we need to remember that as far as hooks, they will start with this use, whether that

5
00:00:20,130 --> 00:00:26,310
is use, in fact, you state use callback use memo or whatever.

6
00:00:26,700 --> 00:00:33,840
So you'll always see this use and that also applies to whatever hooks will create ourselves later on.

7
00:00:34,140 --> 00:00:43,870
We must use this use in the beginning of the components where we invoke those hooks must be the uppercase.

8
00:00:44,730 --> 00:00:46,290
So let me show you the example.

9
00:00:46,290 --> 00:00:53,850
If, for example, I'll change this to a state basics and this is going to be with lowercase, you'll

10
00:00:53,850 --> 00:00:55,680
see a big fat error.

11
00:00:56,010 --> 00:01:03,960
So in order to use hook where there are, as you state, use a fact or whatever, the component needs

12
00:01:03,960 --> 00:01:04,950
to be uppercase.

13
00:01:05,230 --> 00:01:13,650
That is a small gotcher, but a small gotcher that can catch up with you and very random times.

14
00:01:13,990 --> 00:01:19,680
Now also the hook needs to be in the function or component body.

15
00:01:20,160 --> 00:01:24,150
For example, if you move this outside, it's not going to work again.

16
00:01:24,360 --> 00:01:31,140
There's going to be a big fat error because you need to invoke the hook again with the writers, use

17
00:01:31,140 --> 00:01:33,480
state or whichever hook you would want.

18
00:01:33,720 --> 00:01:37,260
It needs to be invoked in the function body.

19
00:01:37,710 --> 00:01:44,550
And then the last thing is something that will take a look at later, and that is that we cannot call

20
00:01:44,550 --> 00:01:45,840
the hook conditionally.

21
00:01:46,110 --> 00:01:49,930
And I'll show you that would use the fact because it's just going to make a little bit more sense.

22
00:01:50,370 --> 00:01:57,330
Now, keep in mind, I'm not talking about the function that we're getting back from the default, because,

23
00:01:57,330 --> 00:02:02,670
of course, in this case, yes, we're calling this conditionally where I'm checking the state value.

24
00:02:02,970 --> 00:02:11,640
And when I'm saying, all right, so if the state is equal to a random title, then I'll invoke my handler

25
00:02:11,640 --> 00:02:12,050
function.

26
00:02:12,420 --> 00:02:13,470
Keep that in mind.

27
00:02:13,770 --> 00:02:15,420
I'm not talking about this function.

28
00:02:15,420 --> 00:02:18,270
Yes, this function you can call conditionally.

29
00:02:18,270 --> 00:02:25,980
However, what I'm talking about is the fact that I cannot just say if I'm in some kind of hook inside

30
00:02:26,160 --> 00:02:28,230
that is not going to work.

31
00:02:28,500 --> 00:02:35,270
And it's going to be easier for me to share with you the fact because there's going to be a proper example.

32
00:02:35,280 --> 00:02:39,060
Again, this applies to all the custom hooks.

33
00:02:39,060 --> 00:02:45,480
We're going to create ourselves, as well as all the hooks that you can use from react, whether or

34
00:02:45,480 --> 00:02:51,570
not use the fact use callback, you state or all the other hooks.