The API WG will focus on creating two different specifications. A low-level JavaScript API and an API/ABI compatible native layer.
Here are some of the goals we will address:
Well Defined: It should have no ambiguity about how functions operate. Everything from explicitly stating when function arguments are coerced and when they aren't, to precisely stating when the function will throw.
Testable: By keeping the API well defined it will be much easier to test. This is key to properly creating a compatibility suit that allows other vendors to create their own implementation and make sure it still functions perfectly well with the existing ecosystem.
Flexible: Being strict and being well defined are not the same thing. By choosing a few key points within the API that give developers more leeway it will be easier for them to create new interfaces. While this API may be more verbose, it will not be restrictive.
Performant: The JS API should be not much more than a means to translate a developers intent down to the native layer. It should barely show up as a blip on any performance benchmarks.
Safe: Errors will propagate safely to the user as often is possible. If an exception is thrown then you'll know something actually went horribly wrong, and the application had no idea how to proceed.
Concisely, the goal for creating a native API:
Create an API/ABI C++ abstraction that is not affected by VM or version which meets the needs of the majority of native modules.