doc: New Promise and Reference docs

PR-URL: nodejs/node-addon-api#243
Reviewed-By: Michael Dawson <michael_dawson@ca.ibm.com>
Reviewed-By: Kyle Farnung <kfarnung@microsoft.com>

doc/promises.md

@@ -1,5 +1,70 @@
-# Promise
-
-You are reading a draft of the next documentation and it's in continuous update so
+You are reading a draft of the next documentation and it's in continuos update so
 if you don't find what you need please refer to:
 [C++ wrapper classes for the ABI-stable C APIs for Node.js](https://nodejs.github.io/node-addon-api/)
+
+# Promise
+
+The Promise class, along with its Promise::Deferred class, implement the ability to create, resolve, and reject Promise objects.
+
+The basic approach is to create a Promise::Deferred object and return to your caller the value returned by the Promise::Deferred::Promise method. For example:
+
+```cpp
+Value YourFunction(const CallbackInfo& info) {
+  // your code goes here...
+  Promise::Deferred deferred = Promise::Deferred::New(info.Env());
+  // deferred needs to survive this call...
+  return deferred.Promise();
+}
+```
+
+Later, when the asynchronous process completes, call either the `Resolve` or `Reject` method on the Promise::Deferred object created earlier:
+
+```cpp
+  deferred.Resolve(String::New(info.Env(), "OK"));
+```
+
+## Promise::Deferred Methods
+
+### Factory Method
+
+```cpp
+static Promise::Deferred Promise::Deferred::New(napi_env env);
+```
+
+* `[in] env`: The `napi_env` environment in which to create the Deferred object.
+
+### Constructor
+
+```cpp
+Promise::Deferred(napi_env env);
+```
+
+* `[in] env`: The `napi_env` environment in which to construct the Deferred object.
+
+### Promise
+
+```cpp
+Promise Promise::Deferred::Promise() const;
+```
+
+Returns the Promise object held by the Promise::Deferred object.
+
+### Resolve
+
+```cpp
+void Promise::Deferred::Resolve(napi_value value) const;
+```
+
+Resolves the Promise object held by the Promise::Deferred object.
+
+* `[in] value`: The N-API primitive value with which to resolve the Promise.
+
+### Reject
+
+```cpp
+void Promise::Deferred::Reject(napi_value value) const;
+```
+
+Rejects the Promise object held by the Promise::Deferred object.
+
+* `[in] value`: The N-API primitive value with which to reject the Promise.

doc/reference.md

@@ -1,5 +1,115 @@
-# Reference
-
-You are reading a draft of the next documentation and it's in continuous update so
+You are reading a draft of the next documentation and it's in continuos update so
 if you don't find what you need please refer to:
 [C++ wrapper classes for the ABI-stable C APIs for Node.js](https://nodejs.github.io/node-addon-api/)
+
+# Reference (template)
+
+Holds a counted reference to a [Value](value.md) object; initially a weak reference unless otherwise specified, may be changed to/from a strong reference by adjusting the refcount.
+
+The referenced Value is not immediately destroyed when the reference count is zero; it is merely then eligible for garbage-collection if there are no other references to the Value.
+
+Reference objects allocated in static space, such as a global static instance, must call the `SuppressDestruct` method to prevent its destructor, running at program shutdown time, from attempting to reset the reference when the environment is no longer valid.
+
+The following classes inherit, either directly or indirectly, from Reference:
+
+* [ObjectWrap](object_wrap.md)
+* [ObjectReference](object_reference.md)
+* [FunctionReference](function_reference.md)
+
+## Methods
+
+### Factory Method
+
+```cpp
+static Reference<T> New(const T& value, uint32_t initialRefcount = 0);
+```
+
+* `[in] value`: The value which is to be referenced.
+
+* `[in] initialRefcount`: The initial reference count.
+
+### Empty Constructor
+
+```cpp
+Reference();
+```
+
+Creates a new _empty_ Reference instance.
+
+### Constructor
+
+```cpp
+Reference(napi_env env, napi_value value);
+```
+
+* `[in] env`: The `napi_env` environment in which to construct the Reference object.
+
+* `[in] value`: The N-API primitive value to be held by the Reference.
+
+### Env
+
+```cpp
+Napi::Env Env() const;
+```
+
+Returns the `Env` value in which the Reference was instantiated.
+
+### IsEmpty
+
+```cpp
+bool IsEmpty() const;
+```
+
+Determines whether the value held by the Reference is empty.
+
+### Value
+
+```cpp
+T Value() const;
+```
+
+Returns the value held by the Reference.
+
+### Ref
+
+```cpp
+uint32_t Ref();
+```
+
+Increments the reference count for the Reference and returns the resulting reference count. Throws an error if the increment fails.
+
+### Unref
+
+```cpp
+uint32_t Unref();
+```
+
+Decrements the reference count for the Reference and returns the resulting reference count. Throws an error if the decrement fails.
+
+### Reset (Empty)
+
+```cpp
+void Reset();
+```
+
+Sets the value held by the Reference to be empty.
+
+### Reset
+
+```cpp
+void Reset(const T& value, uint32_t refcount = 0);
+```
+
+* `[in] value`: The value which is to be referenced.
+
+* `[in] initialRefcount`: The initial reference count.
+
+Sets the value held by the Reference.
+
+### SuppressDestruct
+
+```cpp
+void SuppressDestruct();
+```
+
+Call this method on a Reference that is declared as static data to prevent its destructor, running at program shutdown time, from attempting to reset the reference when the environment is no longer valid.