Operator to set prototype of anonymous object directly

💡 Ideas
1

In a function, if you want to return an object with specific prototype, or no prototype, you may use Object.create, like:
function fun(){
var obj = Object.create(proto);
obj.a=1;
obj.b=2;
return obj;
}

but I just want to return an anonymous object ,i.e. return {a: 1, b:2 }
but current I cannot set the prototype directly.
maybe we need a new operator, for example, "->" to set the prototype.
so we can do something like this: return {a: 1, b: 2} -> proto

1 Like
2

You can do this with { __proto__: proto, a: 1, b: 2 }.

3

The __proto__ definition does only work in object literals, though (and is ugly imo because it looks like a property). An operator could work on arbitrary literals, like the once proposed <| proto operator.

4

That is only guaranteed to work in browser engines - other engines like Rhino and XS are under no obligation to implement that.

5

That depends on what you mean by "obligation". In practice, an engine which omits this will be unable run a lot of extant JS code. For that reason we have discussed pulling a bunch of stuff out of Annex B, including this particular syntax. (And in fact both Rhino and XS do implement it, as do other non-browser engines such as QuickJS and Hermes.)

1 Like