A Napi::Object can be assigned properites via its DefineProperty and DefineProperties functions, which take PropertyDescrptor(s) as their parameters. The Napi::PropertyDescriptor can contain either values or functions, which are then assigned to the Napi::Object. Note that a single instance of a Napi::PropertyDescriptor class can only contain either one value, or at most two functions. PropertyDescriptors can only be created through the class methods Accessor, Function, or Value, each of which return a new static instance of a Napi::PropertyDescriptor.
```cpp
using namespace Napi;
Value TestGetter(const CallbackInfo& info) { return Boolean::New(info.Env(), testValue); }
void TestSetter(const CallbackInfo& info) {
testValue = info[0].As
Value TestFunction(const CallbackInfo& info) { return Boolean::New(info.Env(), true); }
Void Init(Env env) { // Create an object. Object obj = Object::New(env);
// Accessor PropertyDescriptor pd1 = PropertyDescriptor::Accessor(env, obj, "pd1", TestGetter); PropertyDescriptor pd2 = PropertyDescriptor::Accessor(env, obj, "pd2", TestGetter, TestSetter); // Function PropertyDescriptor pd3 = PropertyDescriptor::Function(env, "function", TestFunction); // Value Boolean true_bool = Boolean::New(env, true); PropertyDescriptor pd4 = PropertyDescriptor::Value("boolean value", Napi::Boolean::New(env, true), napi_writable);
// Assign properties to the object. obj.DefineProperties({pd1, pd2, pd3, pd4}); } ```
cpp
Napi::PropertyDescriptor::PropertyDescriptor (napi_property_descriptor desc);
[in] desc: A PropertyDescriptor that is needed in order to create another PropertyDescriptor.cpp
static Napi::PropertyDescriptor Napi::PropertyDescriptor::Accessor (___ name,
Getter getter,
napi_property_attributes attributes = napi_default,
void *data = nullptr);
[in] name: The name used for the getter function.[in] getter: A getter function.[in] attributes: Potential attributes for the getter function.[in] data: A pointer to data of any type, default is a null pointer.Returns a PropertyDescriptor that contains a function.
The name of the property can be any of the following types:
- const char*
- const std::string &
- napi_value value
- Napi::Name
This signature is deprecated. It will result in a memory leak if used.
cpp
static Napi::PropertyDescriptor Napi::PropertyDescriptor::Accessor (
Napi::Env env,
Napi::Object object,
___ name,
Getter getter,
napi_property_attributes attributes = napi_default,
void *data = nullptr);
[in] env: The environemnt in which to create this accessor.[in] object: The object on which the accessor will be defined.[in] name: The name used for the getter function.[in] getter: A getter function.[in] attributes: Potential attributes for the getter function.[in] data: A pointer to data of any type, default is a null pointer.Returns a Napi::PropertyDescriptor that contains a Getter accessor.
The name of the property can be any of the following types:
- const char*
- const std::string &
- Napi::Name
cpp
static Napi::PropertyDescriptor Napi::PropertyDescriptor::Accessor (___ name,
Getter getter,
Setter setter,
napi_property_attributes attributes = napi_default,
void *data = nullptr);
[in] name: The name of the getter and setter function.[in] getter: The getter function.[in] setter: The setter function.[in] attributes: Potential attributes for the getter function.[in] data: A pointer to data of any type, default is a null pointer.Returns a Napi::PropertyDescriptor that contains a Getter and Setter function.
The name of the property can be any of the following types:
- const char*
- const std::string &
- napi_value value
- Napi::Name
This signature is deprecated. It will result in a memory leak if used.
cpp
static Napi::PropertyDescriptor Napi::PropertyDescriptor::Accessor (
Napi::Env env,
Napi::Object object,
___ name,
Getter getter,
Setter setter,
napi_property_attributes attributes = napi_default,
void *data = nullptr);
[in] env: The environemnt in which to create this accessor.[in] object: The object on which the accessor will be defined.[in] name: The name of the getter and setter function.[in] getter: The getter function.[in] setter: The setter function.[in] attributes: Potential attributes for the getter function.[in] data: A pointer to data of any type, default is a null pointer.Returns a Napi::PropertyDescriptor that contains a Getter and Setter function.
The name of the property can be any of the following types:
- const char*
- const std::string &
- Napi::Name
cpp
static Napi::PropertyDescriptor Napi::PropertyDescriptor::Function (___ name,
Callable cb,
napi_property_attributes attributes = napi_default,
void *data = nullptr);
[in] name: The name of the Callable function.[in] cb: The function[in] attributes: Potential attributes for the getter function.[in] data: A pointer to data of any type, default is a null pointer.Returns a Napi::PropertyDescriptor that contains a callable Napi::Function.
The name of the property can be any of the following types:
- const char*
- const std::string &
- napi_value value
- Napi::Name
This signature is deprecated. It will result in a memory leak if used.
cpp
static Napi::PropertyDescriptor Napi::PropertyDescriptor::Function (
Napi::Env env,
___ name,
Callable cb,
napi_property_attributes attributes = napi_default,
void *data = nullptr);
[in] env: The environment in which to create this accessor.[in] name: The name of the Callable function.[in] cb: The function[in] attributes: Potential attributes for the getter function.[in] data: A pointer to data of any type, default is a null pointer.Returns a Napi::PropertyDescriptor that contains a callable Napi::Function.
The name of the property can be any of the following types:
- const char*
- const std::string &
- Napi::Name
cpp
static Napi::PropertyDescriptor Napi::PropertyDescriptor::Value (___ name,
napi_value value,
napi_property_attributes attributes = napi_default);
The name of the property can be any of the following types:
- const char*
- const std::string &
- napi_value value
- Napi::Name
napi_property_attributes are flags used to indicate to JavaScript certain permissions that the property is meant to have. The following are the flag options:
- napi_default,
- napi_writable,
- napi_enumerable,
- napi_configurable
For more information on the flags and on napi_property_attributes, please read the documentation here.