doc: some fix on Napi::Boolean documentation

PR-URL: nodejs/node-addon-api#354
Reviewed-By: Michael Dawson <michael_dawson@ca.ibm.com>

doc/boolean.md

@@ -1,29 +1,64 @@
 # Boolean
 
-# Methods
+`Napi::Boolean` class is a representation of the JavaScript `Boolean` object. The
+`Napi::Boolean` class inherits its behavior from the `Napi::Value` class
+(for more info see: [`Napi::Value`](value.md)).
+
+## Methods
 
 ### Constructor
 
+Creates a new empty instance of an `Napi::Boolean` object.
+
 ```cpp
-Napi::Boolean::New(Napi::Env env, bool value);
+Napi::Boolean::Boolean();
 ```
- - `[in] env`: The `napi_env` Environment
- - `[in] value`: The Javascript boolean value
+
+Returns a new _empty_  `Napi::Boolean` object.
+
+### Contructor
+
+Creates a new instance of the `Napi::Boolean` object.
 
 ```cpp
-Napi::Boolean::Boolean();
+Napi::Boolean(napi_env env, napi_value value);
 ```
-returns a new empty Javascript Boolean value type.
 
-### operator bool
-Converts a `Napi::Boolean` value to a boolean primitive.
+- `[in] env`: The `napi_env` environment in which to construct the `Napi::Boolean` object.
+- `[in] value`: The `napi_value` which is a handle for a JavaScript `Boolean`.
+
+Returns a non-empty `Napi::Boolean` object.
+
+### New
+
+Initializes a new instance of the `Napi::Boolean` object.
+
 ```cpp
-Napi::Boolean::operator bool() const;
+Napi::Boolean Napi::Boolean::New(napi_env env, bool value);
 ```
+- `[in] env`: The `napi_env` environment in which to construct the `Napi::Boolean` object.
+- `[in] value`: The primitive boolean value (`true` or `false`).
+
+Returns a new instance of the `Napi::Boolean` object.
 
 ### Value
+
 Converts a `Napi::Boolean` value to a boolean primitive.
 
 ```cpp
 bool Napi::Boolean::Value() const;
 ```
+
+Returns the boolean primitive type of the corresponding `Napi::Boolean` object.
+
+## Operators
+
+### operator bool
+
+Converts a `Napi::Boolean` value to a boolean primitive.
+
+```cpp
+Napi::Boolean::operator bool() const;
+```
+
+Returns the boolean primitive type of the corresponding `Napi::Boolean` object.

test/basic_types/boolean.cc

@@ -6,10 +6,27 @@ Value CreateBoolean(const CallbackInfo& info) {
   return Boolean::New(info.Env(), info[0].As<Boolean>().Value());
 }
 
+Value CreateEmptyBoolean(const CallbackInfo& info) {
+  Boolean* boolean = new Boolean();
+  return Boolean::New(info.Env(), boolean->IsEmpty());
+}
+
+Value CreateBooleanFromExistingValue(const CallbackInfo& info) {
+  Boolean* boolean =  new Boolean(info.Env(), info[0].As<Boolean>());
+  return Boolean::New(info.Env(), boolean->Value());
+}
+
+Value CreateBooleanFromPrimitive(const CallbackInfo& info) {
+  bool boolean = info[0].As<Boolean>();
+  return Boolean::New(info.Env(), boolean);
+}
+
 Object InitBasicTypesBoolean(Env env) {
   Object exports = Object::New(env);
 
   exports["createBoolean"] = Function::New(env, CreateBoolean);
-
+  exports["createEmptyBoolean"] = Function::New(env, CreateEmptyBoolean);
+  exports["createBooleanFromExistingValue"] = Function::New(env, CreateBooleanFromExistingValue);
+  exports["createBooleanFromPrimitive"] = Function::New(env, CreateBooleanFromPrimitive);
   return exports;
 }

test/basic_types/boolean.js

@@ -11,4 +11,20 @@ function test(binding) {
 
   const bool2 = binding.basic_types_boolean.createBoolean(false);
   assert.strictEqual(bool2, false);
+
+  const emptyBoolean = binding.basic_types_boolean.createEmptyBoolean();
+  assert.strictEqual(emptyBoolean, true);
+
+  const bool3 = binding.basic_types_boolean.createBooleanFromExistingValue(true);
+  assert.strictEqual(bool3, true);
+
+  const bool4 = binding.basic_types_boolean.createBooleanFromExistingValue(false);
+  assert.strictEqual(bool4, false);
+
+  const bool5 = binding.basic_types_boolean.createBooleanFromPrimitive(true);
+  assert.strictEqual(bool5, true);
+
+  const bool6 = binding.basic_types_boolean.createBooleanFromPrimitive(false);
+  assert.strictEqual(bool6, false);
+
 }