Works with ES6 proxy

[yorkie]

The Proxy's get trap handler would deal with the followings:

• a.b property accessor.
• a[b] item accessor.

Does this mean that the slice syntax will be merged into 2nd, the item accessor? If yes, we have to extend the handler arguments, because it's 3 at most as:

{
  get: function(target, start, stop, step) {...}
}

(Actually Proxy/ES doesn't have distinct declaration about the above 2 accessors, it makes developers confused a bit, and hard to extend for special item accessor like slice notation).

[j-f1]

If a well-known Symbol method ends up being used, I’d guess it would call the get trap to get the value of the method, then call it with the slice info.

[yorkie]

@j-f1 do you have any example here? IMO the issue is how to resolve the arguments conflict of get trap on the proxy object o[x:y:z].

[ljharb]

@yorkie you're assuming that slice notation would be a new kind of complex Get. @j-f1 is saying it could be a Get of a Symbol.slice function, which is then invoked - which would not require any changes in Proxy.

[yorkie]

Thank you @ljharb, it resolves the problem eventually, and the slice notation is not going to get object property, the intention of the Proxy get handler at MDN:

The handler.get() method is a trap for getting a property value.