til/javascript/destructure-with-access-to-nested-value-and-parent-value.md

Destructure With Access To Nested Value And Parent Value

A destructuring pattern that I often see (especially in React code) is to peel off a nested value in the argument declaration of a function.

const Component = ({ data: { name: displayName }}) => {
  return (
    <div>
      <h1>{displayName}</h1>
      <SubComponent />
    </div>
  );
};

On its own this works quite well, but what happens when you need access to the full set of data as well as the nested name value? I often see this.

const Component = ({ data }) => {
  const { name: displayName } = data;
  return (
    <div>
      <h1>{displayName}</h1>
      <SubComponent data={data} />
    </div>
  );
};

ES6 destructuring is flexible. You can skip the const line and keep everything in the argument declaration.

const Component = ({ data: { name: displayName }, data }) => {
  return (
    <div>
      <h1>{displayName}</h1>
      <SubComponent data={data} />
    </div>
  );
};

You can re-reference the data value after the nested destructuring.