How to destructure a nested object only when it has a value?

Question

  let notStudent, name, isRegistered
  if (studentDetail && studentDetail.fields) {
    ({ notStudent, name, isRegistered } = studentDetail.fields)
  }

Is there a way to write this logic without an if statement or in a succinct way?

Answer 1

You can destructure in this way. The tricky thing is when there is no fields property on studentDetail then javascript can throw an error, to tackle that case, you can set default empty object using || operator.

let studentDetail = {
  fields: {
    notStudent: '1',
    name: '2',
    isRegistered: true
  }
}

let {
  notStudent,
  name,
  isRegistered
} = (studentDetail && studentDetail.fields) || {};

console.log(notStudent);
console.log(name);
console.log(isRegistered);

Answer 2

You can destructure an empty default object in case your studentDetail.fields doesn't exist:

const { notStudent, name, isRegistered } = studentDetail?.fields ?? {};