On Wed, Jan 8, 2014 at 3:59 AM, Maciej Jaros <e...@wp.pl> wrote:
> To my understanding private name objects are supposed to make private
> properties and functions available for new classes syntax in ECMAScript 6
> standard.
>
> But the syntax is rather strange:
> ```
> var myPrivate = new Name();
> class Test {
> constructor(foo) {
> this[myPrivate] = foo;
> }
> }
> ```
>
>
Private names were replaced by the not-private Symbol. Symbol is a symbol,
private if you keep it that way and public if you expose it.
> I understand the motivation - using just `this[myPrivate]` wouldn't work
> because it could be inconsisten when `myPrivate` is a string variable.
Symbol produces symbols, not strings.
> If `myPrivate='abc'` then `this[myPrivate]` is equivalent `this.abc`... So
> that is the main reason Name objects were born, right?
>
If the symbol was used to create the property, and the binding undergoes a
reassignment, the property won't be accessible via property access by
bracket notation:
var o = {};
var s = Symbol();
o[s] = 1;
o[s];
// 1
s = "s";
o[s];
// undefined
You could still get the Symbol by Object.getOwnPropertySymbols(o)... again
there is no implied privacy with Symbols.
Rick
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