ES6 Proxy Proposal as new base for wrapping Functions and Properties

[danShumway]

Problem: wrapped functions may not catch existing references to function.

• the previous solution for this was to be hyper aggressive about catching references by mass-infecting the entire codebase. This does not lend itself to an isolated, on-demand approach to debugging.
• do not wrap functions automatically, instead relying on things like arguments.callee to try and polyfill support. This severely limits the code analysis capabilities of vAnalyze.

Problem: Host properties need to continually refresh themselves / Host must continuously check for new properties.

• previous solution was to grin and bear it.

Possible future solution: Implement 2-way synchronous data-synchronization using ES6 Proxies and by infecting the prototype chain with invisible objects.

• pros:
  • Provide a safe way to wrap functions and properties with minimal impact to running code.
  • Potentially simplifies codebase, bridging some of the implementation gaps between normal infections, infection wrappers, and properties and unifying how vAnalyze attacks each object.
• cons:
  • Would break compatibility with Chrome (for as long as it takes for them to get primitive support for the feature)
  • Current implementations I've played around with break instanceof. Unsure of what would be required to get this back.
• todo:
  • finalize code samples of how this would work (will be linked here) and what the limitations/benefits would actually be.
  • do a little bit of research into performance impact (forces modifying of prototype chain, which (amazingly) I have largely avoided up until now.
  • decide on the potential impact of dropping Chrome support.

[danShumway]

Basic proposal script is up here: http://jsfiddle.net/danShumway/evrdgxjc/ - reminder that it won't work on Chrome.

This fixes the problem with instanceof as well as demonstrates some test cases. Basically the way that it works is to generate an Infection object (distinct from what we normally return) that is attached to the prototype of a Host. The code is then returned a Proxy object linked to that Infection.

The result is that accessing either object will result in up-to-date information about the other object.

To adapt this to vAnalyze's use-case, I would likely attach additional code to the call handler, as well as log additional information whenever anything is accessed via the proxy.