How to copy an object structure without the property values?

Question

I have found myself needing to copy the structure of an object without any values.

For example:

var foo = {
  name: 'Leo',
  address: '1234 Road'
}

var bar = someFunction(foo);

// bar now should equal:
// {
//   name: undefined,
//   address: undefined
// }

I do realize I can loop through the object keys and assign to the result, was just hoping there might be a simpler method.

Note: I chose the answer I did because it is the one I decided to use, but all the answers were excellent.

Answer 1

Using Object.keys() to get properties of original object first. Secondly you can use for example Array.prototype.reduce() to create a new object with the expected keys and values.

This can work for you:

const foo = {
  name: 'Leo',
  address: '1234 Road'
};

const result = Object.keys(foo).reduce((a,c) => {
  a[c] = undefined;
  return a;
}, {});

console.log(result);

I hope that helps!