Why are vairable declaration different when we assign the value useState("")? [duplicate] - javascript

This question already has answers here:
What does this symbol mean in JavaScript?
(1 answer)
Multiple assignment in JavaScript? What does `[ a, b, c ] = [ 1, 2, 3 ]` mean?
(4 answers)
Closed 9 months ago.
This is what confuses me alot:
When we give a variable a for an example a empty string we do it like this:
const empty = ""
But for useState we do it like this:
const [color, setColor] = useState("Black")
But why? I get so confused that the syntax for useState looks like that.
And ofc searching did not help me.

Related

What does this declaration mean in javascript [duplicate]

This question already has answers here:
Syntax - what does square brackets around a variable declaration mean [duplicate]
(1 answer)
Multiple assignment in JavaScript? What does `[ a, b, c ] = [ 1, 2, 3 ]` mean?
(4 answers)
Javascript. Assign array values to multiple variables? [duplicate]
(2 answers)
Closed 8 months ago.
Consider the declarations of variable "x" and "y"
const x = 1;
const [y] = [1]
What is the meaning of 2nd declaration?
Can someone suggest an article about such declaration type.
This is destructuring assignment.
You are unpacking values from arrays or object properties.
In your above code, a const variable y will be defined with value 1.

What is going on with this assignment? [duplicate]

This question already has answers here:
Multiple assignment in JavaScript? What does `[ a, b, c ] = [ 1, 2, 3 ]` mean?
(4 answers)
What is destructuring assignment and its uses?
(3 answers)
Closed 2 years ago.
Can someone explain me what is going on here?
const [counter, setCounter] = useState(0);
Is it some kind of assignment?
I think you might need to take a look into the React Hooks docs
It's a destructuring assignment on the results of calling the useState function:
the first element of the array is the value
the second element is a function to change value.

I want to know the const declaration type of js [duplicate]

This question already has answers here:
Javascript object bracket notation ({ Navigation } =) on left side of assign
(5 answers)
What is destructuring assignment and its uses?
(3 answers)
Closed 3 years ago.
I know how to declare const variable like const a = 1;
but I dont get what is this
const { app, BrowserWindow } = require('electron')
can anyone explain me?
That’s a destructuring assignment.
https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Destructuring_assignment
It lets you make shortcuts to members of an array or structure.

Syntax - what does square brackets around a variable declaration mean [duplicate]

This question already has answers here:
Multiple assignment in JavaScript? What does `[ a, b, c ] = [ 1, 2, 3 ]` mean?
(4 answers)
Closed 5 years ago.
Take the following line of code
const [component] = router.getMatchedComponents({ ...to })
Could anyone advise what the square brackets around component means here? I have tried to google this but struggling to find an answer
It's called Destructuring assignment, and it's used to unpack the values of an array and assign them to new variables.
So here in your code:
const [component] = router.getMatchedComponents({ ...to })
You are assigning to the component variable the first element held in the array that will be returned by router.getMatchedComponents({...to}), where to is an array-like structure turned into object using the spread operation.

What is this syntax in JavaScript [duplicate]

This question already has answers here:
Multiple assignment in JavaScript? What does `[ a, b, c ] = [ 1, 2, 3 ]` mean?
(4 answers)
Closed 5 years ago.
Take the following line of code
const [component] = router.getMatchedComponents({ ...to })
Could anyone advise what the square brackets around component means here? I have tried to google this but struggling to find an answer
It's called Destructuring assignment, and it's used to unpack the values of an array and assign them to new variables.
So here in your code:
const [component] = router.getMatchedComponents({ ...to })
You are assigning to the component variable the first element held in the array that will be returned by router.getMatchedComponents({...to}), where to is an array-like structure turned into object using the spread operation.

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