One of the neat things about JavaScript 1.7 and up is the support for array destructuring. It allows you to do things like

function foo() { return [5, 10]; }
let [a, b] = foo();

or even

function bar([a, b]) { return a + b; }
bar([5, 10]);

While the first example is obviously useful, the second one is somewhat less so. However, I didn’t know just how useful the general idea behind the second example is until this weekend, when asuth pointed out on IRC something I’d been previously unaware of: JavaScript supports object destructuring too. This means that you can do stuff such as

function baz() { return {a: 5, b: 10}; }
let {a: x, b: y} = baz();

Here, x and y will be 5 and 10 respectively at the end.

And yes, you can even write

function quux({a: x, b: y}) { return x + y; }
quux({a: 5, b: 10});

This looks like a great way to implement named parameters for your functions whenever you need them.

But wait – there’s more! There’s even a shorthand for when the property name is the same as the name of the variable you want to assign to. The last example could be rewritten as

function quux({a, b}) { return a + b; }
quux({a: 5, b: 10});

Depending on your use case, this might be an even better way to implement named parameters!

Note that the shorthand only works for destructuring assignments – you can’t use it to create (or “structure”) objects.