This question already has answers here:
Javascript object bracket notation ({ Navigation } =) on left side of assign
(5 answers)
Closed 4 years ago.
Are these constructions the same?
const {PI} = Math;
and
const PI = Math.PI;
What are benefits of using the first example?
The curly braces around the variable name is called Destructuring assignment,
and const {PI} = Math; will translate to const PI = Math.PI
It is a so-called "destructuring assignment".
Searching this site I found a similar question with a good answer:
Javascript (ES6) const with curly braces
Related
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.
This question already has answers here:
What does curly brackets in the `var { ... } = ...` statements do?
(4 answers)
Closed 4 years ago.
I upgraded a npm and now my webpack fails around this line here.
const { theme } = params;
What does this mean when you have { } around the variable name?
This is called destructuring assignment. The destructuring assignment syntax is a JavaScript expression that makes it possible to unpack values from arrays, or properties from objects, into distinct variables.
This question already has answers here:
Javascript object bracket notation ({ Navigation } =) on left side of assign
(5 answers)
What does this symbol mean in JavaScript?
(1 answer)
Closed 4 years ago.
I can't seem to find anything in the documentation to understand why the { and } characters are wrapped around variables on some examples I've seen. Can anyone example why we would do that?
For example:
const {app} = require('./app/app.js');
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.
This question already has answers here:
Javascript object bracket notation ({ Navigation } =) on left side of assign
(5 answers)
ES6 Object Destructuring Default Parameters
(1 answer)
Closed 6 years ago.
I was reading the source for a MeteorJS package (this one) when I came across this:
const {
getMeteorData,
pure = true,
} = expandedOptions;
I did some research to figure out what this code would do, but couldn't find any other instance of const being used like this, or any documentation to clarify it for me.
Any hints, please?
It is using es6 to unpack (or destructure) the values inside the expandedOptions object.
const val = {a:1, b:"hello"};
const {
a,
b
} = val;
console.log(a); //1
console.log(b); //"hello"