hi everyone i am new to react native. Reading the documentation and seeing various examples, I didn't quite understand a few things:
- code:
const Hello = () => {
return (
<div>hello</div>
)
}
and code:
Hello() {
return (
<div>Hello</div>
)
}
are the same, i.e. do they have the same meaning?and how can I recall them for example when the application starts?
2)and what is the meaning of: const [A, B] = useState ()
? what do A and B mean?
CodePudding user response:
Ahh , see for first its mostly a Javascript thing. in RN we return JSX
const Hello = () => {
return (
<div>hello</div>
)
}
stands for const fun = () => {}
And this
Hello() {
return (
<div>Hello</div>
)
}
stands for function fun() {}
Thats it.
For point 2 :
const [name, setName] = useState ("johndoe") // 0 is default value
useState
is a hook , which is a react feature, here for suppose you want a variable called name
and you want to display it in your app.
IF you just do let name = "johndoe"
in react and render it, it will display john doe
. But if you update its value like name = "messi"
, in app screen it will still display john doe
rather than messi
.
Hence there's useState
which rerenders
the screen. So for above
you can update name via setName("messi")
and voila you now get messi
being displayed in app.
i suggest you to follow this YT article to understand better
Hope it helps. feel free for doubts