Define iterator for `Napi::Array` for using with ranged for-loop or STL algorithms

[aminya]

Currently, the only way to loop over the Napi::Array is to maintain the index manually and loop over using traditional for loops:

    auto napiArray = Napi::Array::New(info.Env());
	for (uint32_t i = 0, len = cppVector.size(); i < len; i++) {
        napiArray[i] = Napi::Number::New(info.Env(), cppVector[i]);
    }

However, I'd like to be able to use ranged for loop or STL algorithms:

    auto napiArray = Napi::Array::New(info.Env());
    std::transform(cppVector.begin(), cppVector.end(), napiArray.begin(), 
	[&info](auto a) { return Napi::Number::New(info.Env(), a); });

or other similar examples

[RaisinTen]

@aminya perhaps you mean an iterator for Napi::Object because Napi::Array inherits from Napi::Object. What should the iterator invalidation rules be?

[aminya]

We shouldn't necessarily use the same iterator for these two types. I expect the Array to work the same as std::vector. But Napi::Object is more similar to std::map.

[github-actions]

This issue is stale because it has been open many days with no activity. It will be closed soon unless the stale label is removed or a comment is made.

[aminya]

Unstale

[mhdawson]

We discussed in the Node-API team meeting today and it seems reasonable but it might be a more complicated due to sparse arrays etc. @aminya would you be able to submit a PR?

[RaisinTen]

PR to add an iterator for Napi::Object: #930

[aminya]

This isn't fixed yet, though.