Introduction to useState
Telmo Goncalves
Posted on March 5, 2020
I've been working with React Hooks for some time now and I thought about writing a quick and simple post on how to use useState
.
Let us get started
First of all, we need to import useState
from react
import React, { useState } from 'react'
Take into account the following function:
import React, { useState } from 'react'
function Steps() {
return (
<div>
Today I've walked 0 steps.
</div>
)
}
Alright, we want to control the amount of steps we've walked today, for that we can use the useState
method, let us take a look:
import React, { useState } from 'react'
Take into account the following function:
import React, { useState } from 'react'
function Steps() {
const [steps] = useState(0)
return (
<div>
Today I've walked {steps} steps.
</div>
)
}
What are we doing here?
- Creating a new state called
steps
and its default value is0
- We're printing our
steps
value in our function
Control
Now we want to control the value of steps
, with useState
you can destructure another prop, so, currently we have const [steps]
, we will get another method from there, let us change that to const [steps, setSteps]
.
Now we've introduced setSteps
, with this we can control the value of steps
, let us create a button to handle an onClick
function to set the steps to 10
, try it out
import React, { useState } from 'react'
function Steps() {
const [steps, setSteps] = useState(0)
const increaseSteps = () => setSteps(10)
return (
<div>
Today I've walked {steps} steps.
<button onClick={() => increaseSteps()}>
Increase steps
</button>
</div>
)
}
When you click on our new button
the steps should increase to 10
, great.
We can do better
We might want to increase the steps by 1
, not 10
. You might be thinking it's as simple as changing 10
with 1
, give it a try, I'll wait.
It only goes to 1
right? 🤷♂️
Nothing to worry, we'll fix it right now, change the increaseSteps()
function:
const increaseSteps = () => setSteps(steps + 1)
What are we doing? We're getting the value of steps
and increasing it by one.
You can also create another button to decrease the value, similar function but using -1
:
const decreaseSteps = () => setSteps(steps - 1)
Result
I've spiced things a little bit with styling and an emoji 🙂
You can check the final code in this Codesandbox
If you liked this post consider following me on Twitter, appreciate it 🙂
Posted on March 5, 2020
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