Object destructuring on variable reassignment

[hiimjako]

Hi, I have encountered unreadable behavior, in my opinion, when reassigning a variable from an object that contains a key with the same name as the variable, for example:

let foo = null
try {
  const response = await apiCall()
  foo = response.foo // eslint error: Use object destructuring.eslintprefer-destructuring
} catch (error) {
  console.error(error)
}

This behavior is managed by prefer-destructuring ESLint rule. The way it is currently set up, it forces you to adjust the code like this:

let foo = null
try {
  const response = await apiCall();
  ({ foo } = response.foo) // No eslint errors
} catch (error) {
  console.error(error)
}

I was wondering if it wouldn't be more readable to adjust the rule to allow the reassignment as shown in the first example.
It could be modified by updating the rule like this:

"rules": {
  ...
  "prefer-destructuring": ["error", {
    "VariableDeclarator": {
      "array": true,
      "object": true
    },
    "AssignmentExpression": {
      "array": true,
      "object": false
    }
  }]	
}

This would not be a breaking change, because both syntaxes will work without throwing ESLint errors.

[davidebianchi]

Hi @hiimjako, I think this change it's ok. For sure, it is better the assignment.
Can you add a PR?

[cescobaz]

I think that linter is suggesting the following:

const { foo } = await apiCall();

You don't need the response variable, in my opinion it is clean.

[davidebianchi]

Yes, sure this could be done. In this case where you want to set in a variable, you should have another variable name instead.
Here we could talk about if the try/catch clause with external reference is a good pattern to use, but it's sure better than nested try/catch clause imho.

[hiimjako]

I think that linter is suggesting the following:

const { foo } = await apiCall();

You don't need the response variable, in my opinion it is clean.

It is not either possible, for this reasons:

1. In the example provided in the issue I'm not declaring the variable, it is already declared and I am reassigning it;
2. You can do something like this

({ foo } = await apiCall())

But if you have a previous statement, you have to use a semicolumn;
3. As shown in step 2, you have to put it inside the parentheses and I think it is better to avoid this syntax if possible in this cases.

As said by @davidebianchi you should have another variable name to do that, but to me, it appears a workaround changing variables names to satisfy linter.