const obj = { a: 1, b: 2, c: 3, d: 4 };

// Rest properties
const { a, b, ...rest } = obj;
console.log(rest); // { c: 3, d: 4 }

// Spread properties
const newObj = { ...obj, e: 5 };
console.log(newObj); // { a: 1, b: 2, c: 3, d: 4, e: 5 }

Promise.finally

Execute code regardless of whether a promise is fulfilled or rejected.

fetch("/api/data")
  .then(response => response.json())
  .then(data => console.log(data))
  .catch(error => console.error(error))
  .finally(() => {
    console.log("Request completed");
  });

Asynchronous Iteration

Iterate over async iterables using for-await-of loop.

async function* asyncGenerator() {
  yield Promise.resolve(1);
  yield Promise.resolve(2);
  yield Promise.resolve(3);
}

async function example() {
  for await (const num of asyncGenerator()) {
    console.log(num); // 1, 2, 3
  }
}