This technique is useful when you don't know the property name ahead of time and still want to destructure it cleanly. I often use this for deleting keys from an object. Useful in state reducers.

const keyToExtract = "email";
const user = {
  name: "Sen",
  email: "sen@senhongo.com",
  role: "guy"
};

const { [keyToExtract]: extractedValue, ...rest } = user;

console.log(extractedValue); // sen@senhongo.com
console.log(reset); // { name: "Sen", role: "guy" }

keyToExtract is a dynamic variable that holds the name of the key we want to pull out.
The property with the key email is extracted into extractedValue.
The rest of the object goes into rest.

Object destructuring with dynamic keys