ES2015 destructiring assignment with renaming causes key-spacing

I’m seeing this key-spacing error for reassignment during destructuring, as done here :

https://developer.mozilla.org/en/docs/Web/JavaScript/Reference/Operators/Destructuring_assignment#Assigning_to_new_variable_names

I accept that it might be considered appropriate to add a space after the colon, as in the case of a key/value pair, but the wording of the error is a little misleading since it isn’t a key/value pair. Is it worth rewording the error message, or at least adding such an example to the docs so people can see it is not a mistake?

Tell us about your environment

• ESLint Version: v3.19.0
• Node Version: v7.8.0
• npm Version: 4.2.0

What parser (default, Babel-ESLint, etc.) are you using? ?

Please show your full configuration:

{
  "extends": ["eslint:recommended", "google"],
  "env": {
    "browser": true,
    "es6": true
  },
  "plugins": [
    "html"
  ],
  "rules": {
    "no-var": "off",
    "new-cap": ["error", { "capIsNewExceptions": ["Polymer", "PolymerRedux"] }],
    "no-console": ["error", { "allow": ["info", "warn", "error"] }]
  },
  "globals": {
    "Polymer": true
  },
  "parserOptions": {
    "ecmaVersion": 6
  }
}

What did you do? Please include the actual source code causing the issue.

let {b:c} = {a: 1};

What did you expect to happen? Nothing: ie is it acceptable for there to be no space after the ‘:’ when renaming during destructuring, or: A relevant, helpful error message, such as ‘Missing space before assigned variable in destructuring’ - I’m sure there is something better than that.

What actually happened? Please include the actual, raw output from ESLint.

  1:8  error  Missing space before value for key 'b'  key-spacing
  1:8  error  'c' is assigned a value but never used  no-unused-vars

✖ 2 problems (2 errors, 0 warnings)

The current message is un-intuitive (imo) since it references a key-value pair, and this isn’t that.

https://developer.mozilla.org/en/docs/Web/JavaScript/Reference/Operators/Destructuring_assignment#Assigning_to_new_variable_names

Tagging @btmills, as requested.

[chipit24]

Any update on this? I would like to be able to enforce a structure like this:

const myObj = { id: '1234' };
const { id:ObjId } = myObj;

I think disallowing the space after the colon for the renamed variable makes it more clear that it’s a renamed variable and not a value in a key-value pair.

[btmills]

@davidmaxwaterman here’s a less contrived example:

// This:
const {
    location: {
        protocol
    }
} = window;

// Is equivalent to this:
const protocol = window.location.protocol;

Check out nested object destructuring on MDN.