Existential Operator / Null Propagation Operator

[Laurentiu Macovei]

 `foo?.bar` and `foo?['bar']` syntax would work too.

However the using both current `?` `:` operator and `?.` might be very
confusing on the same line.

e.g. using `?.` and `?['prop']`
```js
var a = { x: { y: 1 } };
var b = condition ? a?.x.?y : a?.y?.z;
var c = condition ? a?['x']?['y'] : a?['y']?['z'];
```
as opposed to double dots `..` and `..['prop']`
```js
var a = { x: { y: 1 } };
var b = condition ? a..x..y : a..y..z;
var c = condition ? a..['x']..['y'] : a..['y']..['z'];
```

##### Which one does look more clear to you?
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mail.mozilla.org/pipermail/es-discuss/attachments/20151029/037c63e4/attachment.html>