Functional Destructuring: Destructure via function calls using new syntax

[bergus]

@brandonmcconnell

Having the new variable name/alias inside the function could be very confusing for some, as it's identical to how most functions pass arg(s) functions.

I agree, I didn't expect this idea could satisfy TC39.

@brandonmcconnell

It might be more understandable to invert the function and variable name, like this:

content: wordCount(getWordCount)

No, that won't work, destructuring is designed to have the property name on the left and the target expression (which might contain nested destructuring patterns) on the right.

Actually I think it would work, as far as grammar unambiguity is concerned, to put the "call" on the left side around the property name:

const {
  getDaysSince(date): days,
  getWordCount(content): wordCount,
  getCharCount(["content"]): charCount,
  buildSlugURL(title): {path: slugPath, searchParams: slugParams},
} = article;

But that's still confusing, I'll expect people trying to pass multiple arguments and also things that are not properties into these "calls" which should not work.
I didn't remember @theScottyJam's coercion discussion, but I think I would prefer to have the function in between the property name and the target:

const {
  date via getDaysSince: days,
  content via getWordCount: wordCount,
  ["content"] via getCharCount: charCount,
  title via buildSlugURL: {path: slugPath, searchParams: slugParams},
} = article;

And if you wanted to call the function in a different way, a function expression would work:

  title via (t => buildSlugURL(location.href, t, {relative: true})): {path: slugPath, searchParams: slugParams},

@brandonmcconnell

some properties may need to be built off of multiple properties

Then don't use destructuring for these.
Although indeed using the getters syntax from the extensions proposal would enable this.