使用解构更新 object // 参考

Question

i want update this object(newBook) with destructuring

let newBook ={
   bookId:book._id,
   favorite:false,
}
let {favorite} = newBook
favorite = true

favorite need to be a reference newBook.favorite

i see we can update the original objet like that

let b = newBook
b.favorite = true

but with the destructuring not work, any idea?

Answer 1

Reassigning a variable, by itself, never has any side effects (outside of extremely unusual situations like with arguments and exported ES6 module bindings). If you have

someIdentifier = someExpression

that line alone won't change anything else about the code, except where someIdentifier is used later.

If you want to update the original object, the only real way is to assign to a property of the object, like you're doing with

b.favorite = true

or

newBook.favorite = true

This doesn't really have anything to do with destructuring. Assigning a property of an object to a new variable just doesn't carry over the reference from the parent object to the new variable.