Proposal to add the null check in objct destructuring syntax

State: -1

Author: @thejoin95 (@thejoin95)

Champion: need one

Object destructuring is well use by the javascript developers. The default value in case of an undefined prop is useful and I think it could be even better if we are going to implement it as well with the null check, especially for a nested object in order to avoid null check errors.

Imagine to have an object with n depth level, e.g. a react state/context with differents properties containing n-depth objects. In some scenario you want to destructure few properties at the first level and in other case also some more specific in-depth props.

const state = {
  navbar: {
    profileMenu: {
      username: 'jhondoe',
      ...
    }
  },
  footer: {
    brand: {
      title: 'brand one',
      ...
    }
  },
  ...
}

const {
  navbar: {
    profileMenu: {
      username: ProfileMenuUsername
    }
  }
} = state;

Let's say that, the properties are going to be valorised but some of them would have a null value:

{
  navbar: {
    profileMenu: null,
  },
  footer: {
    brand: {
      title: 'brand one',
      ...
    }
  },
  ...
}

const {
  navbar: {
    profileMenu: {
      username: ProfileMenuUsername
    }
  }
} = state; // this will break because there is no valid username prop in null

When a nested property is undefined, we could assign the default value, defined in the object destructuring syntax:

const {
  navbar: {
    profileMenu: {
      username: ProfileMenuUsername
    } = { username: null }
  } = { profileMenu: { username: null } }
} = state;

It would be great to have a syntax to indicate whenever a property could be nullable by adding a short circuit instead of throwing an error by reusing the .?, such like:

const {
  navbar: {
    profileMenu?: {
      username: ProfileMenuUsername
    } = { username: null }
  } = { profileMenu: { username: null } }
} = state;

These npm modules do something like the proposal:

• lodash.get

Even though is a different approach, would say old style, and I believe it should implemented directly on the destructure syntax.

In progress