Samuel Hapák schrieb:
The main idea is, that if object defines `Symbol.get` method, it gets used to
access properties of object instead of `[]` when destructuring.
Aw, when I read "extensible destructuring" I had hoped to see an
extension to the destructuring syntax, not to see how semantics of
destructuring objects are changed.
What do you think about extractor functions, like in Scala
<http://www.scala-lang.org/old/node/112>?
Instead of `unapply` or `unapplySeq` methods we'd probably use an
`@@extractor` (`Symbol.extractor`) method or so, allowing us to do
let Map({a, b, c}) = myMap;
let List(a, b, c) = myList;
const Map({author: Map({name: {first, last}, birthdate})}) = book;
which would desugar to
let [{a, b, c}] = Map[Symbol.extractor](myMap);
let [a, b, c] = List[Symbol.extractor](myList);
const [{author: __author}] = Map[Symbol.extractor](book);
const [{name: {first, last}, birthdate}] =
Map[Symbol.extractor](__author);
where each extractor method would return an Iterable that is assigned to
the "arguments" of the extractor. (A Proxy to lazily destructure object
literals in there is a good idea, thanks @Claude).
This would even allow us to call functions on destructuring, think about
module imports:
// a.js
export default function factory(options) {
…
return moduleInstance;
}
// b.js
const NoOptions = {
[Symbol.extractor](factory) { return [factory()]; }
};
const WithOptions = (...args) => ({
[Symbol.extractor](factory) { return [factory(...args)]; }
});
import NoOptions(A) from "a";
import WithOptions("config")(A) from "a";
// A === moduleInstance
What do you think about that?
Bergi
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