如何在javascript中从对象内部解构数组？

Question

I have an object like this:

obj = {'id': 1, a: [1, 2, 3]}

I want to destructure and get the array a from obj

arr = {...obj.a}

I get:

{0: 1, 1: 2, 2: 3}

which is not an array

How to get the array itself ?

Answer 1

You are spreading an array inside {} . This creates an object with indices of the array as keys. This is why you get {0: 1, 1: 2, 2: 3}

 const a = [ 1, 2 ] console.log({ ...a }) 

If you want to get a property into a variable, this is the correct syntax :

const { propertyName } = yourObject
// if you want to have a variable name which is different than the propertyName
const { propertyName: someOtherVariable } = yourObject

Here's the working snippet:

 const obj = {'id': 1, a: [1, 2, 3] } const { a: arr } = obj; // this is same as: const arr = obj.a console.log(arr) 

Answer 2

You could destructure to an array by assigning the array to an array with a rest syntax.

 var obj = { id: 1, a: [1, 2, 3] }, [...arr] = obj.a; console.log(arr); 

Answer 3

差不多-相反：)

let {a: arr} = {'id': 1, a: [1, 2, 3]}

Answer 4

Use brackets instead of curly braces to spread it into a new array:

 const obj = {'id': 1, a: [1, 2, 3]} const arr = [...obj.a] console.log(arr)