Hi there.
In this video, we're going to talk about custom hooks in react native.
Custom hooks are powerful tool that can
help simplify your code, make it more reusable, and improve its performance.
We'll explain what custom hook are, why they are useful,
what problems they solve, and in what situations you might use them.
Then we'll provide an example of a custom hook and walk you through the code.
So what are custom custom hooks?
Custom hooks are functions that use other
hooks to add functionality to your react native application.
They allow you to encapsulate common logic
in a reusable function that can be used
across different components and projects.
Custom hooks can be used to handle common
tasks such as state management, data fetching, navigation, theming, and more.
So why are they useful?
They are useful because they can help
simplify your code and reduce duplication.
By encapsulating common functionality
in a custom hook, you can make it easier
to share code between
components across projects.
Custom hook can also help to improve
the readability and maintainability
of your code by separating
concerns and reducing duplication.
So what problems do custom hooks solve?
Custom hooks can help to solve several
common problems that arise
in react native applications.
For example, they can help to simplify
state management by abstracting away the details of managing state variables
and providing a simple way for updating and accessing state.
Custom hooks can also help to improve performance by preventing unnecessary
rerenders and optimizing the rendering of complex components.
So when should you use them?
You should consider using custom hook
in any situation where you find yourself
repeating the same code across
different components or projects.
Custom hook can be particularly useful
in complex applications that require a lot
of state management, data fetching,
navigation, theming,
or other common tasks.
They can also be helpful in situations
where you need to optimize the performance
of your application or reduce the amount
of boilerplate code you need to write.
So let's take a look at example of a custom hook.
You're now looking at my editor with my simulator open,
my Metro bundler running, and we're back to our Hello World
application so that we can simply convey the idea of using custom hook.
So let's imagine a scenario where you need to toggle a button.
Okay? So let's create a button here.
I just imported the button from here
and let's give it a title and let's call it a Toggle button.
And then let's say that when you press
this button, you want to toggle the value of the button.
Okay? So in that case,
if you have a button that toggles the value from true to false many times
during your project, in some different cases you could create a use toggle hook.
So let's create a folder here called
Custom hooks and then let's create a new
file and let's call it Use toggle JS.
And here let's create a simple hook
that just toggles the value of a state from true to false or from false to true.
So let's import useState hook from react.
Let's create a use toggle hook and let's set its initial value to be false
and then let's use the value state and set it to initial value that we
pass to this use Toggle function and then let's say that we have a function
that toggles this value and sets value to the opposite value, okay?
And then we just can return the value and the Toggle function.
Let's export this use toggle
function and let's see how we could use it in our application.
So this custom hook uses the useState hook to create a new state variables called
value and a function called set value that can be used to update the state.
It also defines a function called Toggle
that toggles the value of the value variable that we created and finally it
returns an array that contains the current value and the Toggle function.
So if we wanted to use Toggle here we could just create a state and say that we
have an isOn variables and toggle is on setter and we could use the use toggle
that I just imported here and we can give it the initial value of false.
Now, to see this in action,
let's create a text component here and let's say that if the value is on,
we say that it is on, otherwise we say that it is off.
So we see that currently it is off.
But if I press this button
and let's make sure that onpress I use toggle is on setter.
So let's save this again and let's press
this button, we're going to see that it's switched from off state to on state.
So as many times as I press it,
this state will be updated using the use toggle hook that we created.
Now as you know, something like this might
happen a lot in our application where we need to toggle a value from false to true
or from true to false and a hook like this could be useful in a lot of cases.
So in conclusion, custom hooks are a powerful tool that can
help simplify your code, make it more reusable and improve its performance.
By encapsulating common functionality in a custom hook, you can make it easier
to share code between components and across projects.
If you find yourself repeating the same
code across different components or projects, consider creating a custom hook
to encapsulate that logic and make it more reusable.
I hope this video has been helpful
in explaining what custom hooks are, why they are useful,
what problems they solve and in what situation you might use them.
So thanks for watching and I'll see you in the next section.