Using object rest properties to immutably delete multiple keys in runtime

[liyuanqiu]

We know we can get the rest entries of an object:

let { x, y, ...z } = { x: 1, y: 2, a: 3, b: 4 };
x; // 1
y; // 2
z; // { a: 3, b: 4 }

But if the x, y is in an array, for example [ 'x', 'y' ], generated in runtime, I don't know those keys when coding, maybe we need this kind of syntax:

const keys = [ 'x', 'y' ];
// syntax error here, some new syntax is needed
let { ...keys, ...z } = { x: 1, y: 2, a: 3, b: 4 };
x; // 1
y; // 2
z; // { a: 3, b: 4 }

[hax]

@liyuanqiu As lexical scope, all identifiers have to be declared first. So there is no way to magically create x y unless we introduce dynamic scope (like obsolete with statement in non-strict ES5).