Object

The Napi::Object class corresponds to a JavaScript object. It is extended by the following node-addon-api classes that you may use when working with more specific types:

• Napi::Value and extends Napi::Array
• Napi::ArrayBuffer
• Napi::Buffer<T>
• Napi::Function
• Napi::TypedArray.

This class provides a number of convenience methods, most of which are used to set or get properties on a JavaScript object. For example, Set() and Get().

Example

```cpp

include

using namespace Napi;

Void Init(Env env) {

// Create a new instance Object obj = Object::New(env);

// Assign values to properties obj.Set("hello", "world"); obj.Set(uint32_t(42), "The Answer to Life, the Universe, and Everything"); obj.Set("Douglas Adams", true);

// Get properties Value val1 = obj.Get("hello"); Value val2 = obj.Get(uint32_t(42)); Value val3 = obj.Get("Douglas Adams");

// Test if objects have properties. bool obj1 = obj.Has("hello"); // true bool obj2 = obj.Has("world"); // false

} ```

Methods

Empty Constructor

cpp Napi::Object::Object(); Creates a new empty Object instance.

Constructor

cpp Napi::Object::Object(napi_env env, napi_value value); - [in] env: The napi_env environment in which to construct the Value object.

• [in] value: The C++ primitive from which to instantiate the Value. value may be any of:
• bool
• Any integer type
• Any floating point type
• const char* (encoded using UTF-8, null-terminated)
• const char16_t* (encoded using UTF-16-LE, null-terminated)
• std::string (encoded using UTF-8)
• std::u16string
• Napi::Value
• napi_value

Creates a non-empty Napi::Object instance.

New()

cpp Napi::Object Napi::Object::New(napi_env env); - [in] env: The napi_env environment in which to construct the Napi::Value object.

Creates a new Napi::Object value.

Set()

cpp void Napi::Object::Set (____ key, ____ value); - [in] key: The name for the property being assigned. - [in] value: The value being assigned to the property.

Add a property with the specified key with the specified value to the object.

The key can be any of the following types: - napi_value - Napi::Value - const char* - const std::string& - uint32_t

While the value must be any of the following types: - napi_value - Napi::Value - const char* - std::string& - bool - double

Get()

cpp Napi::Value Napi::Object::Get(____ key); - [in] key: The name of the property to return the value for.

Returns the Napi::Value associated with the key property. Returns the value undefined if the key does not exist.

The key can be any of the following types: - napi_value - Napi::Value - const char * - const std::string & - uint32_t

Has()

cpp bool Napi::Object::Has (____ key) const; - [in] key: The name of the property to check.

Returns a bool that is true if the object has a property named key and false otherwise.

InstanceOf()

cpp bool Napi::Object::InstanceOf (const Function& constructor) const - [in] constructor: The constructor Napi::Function of the value that is being compared with the object.

Returns a bool that is true if the Napi::Object is an instance created by the constructor and false otherwise.

Note: This is equivalent to the JavaScript instanceof operator.

DefineProperty()

cpp void Napi::Object::DefineProperty (const Napi::PropertyDescriptor& property); - [in] property: A Napi::PropertyDescriptor.

Define a property on the object.

DefineProperties()

cpp void Napi::Object::DefineProperties (____ properties) - [in] properties: A list of Napi::PropertyDescriptor. Can be one of the following types: - const std::initializer_list& - const std::vector&

Defines properties on the object.

Operator

cpp Napi::PropertyLValue<std::string> Napi::Object::operator[] (const char* utf8name); - [in] utf8name: UTF-8 encoded null-terminated property name.

Returns a Napi::PropertyLValue as the named property or sets the named property.

cpp Napi::PropertyLValue<std::string> Napi::Object::operator[] (const std::string& utf8name); - [in] utf8name: UTF-8 encoded property name.

Returns a Napi::PropertyLValue as the named property or sets the named property.

cpp Napi::PropertyLValue<uint32_t> Napi::Object::operator[] (uint32_t index); - [in] index: Element index.

Returns a Napi::PropertyLValue or sets an indexed property or array element.

cpp Napi::Value Napi::Object::operator[] (const char* utf8name) const; - [in] utf8name: UTF-8 encoded null-terminated property name.

Returns the named property as a Napi::Value.

cpp Napi::Value Napi::Object::operator[] (const std::string& utf8name) const; - [in] utf8name: UTF-8 encoded property name.

Returns the named property as a Napi::Value.

cpp Napi::Value Napi::Object::operator[] (uint32_t index) const; - [in] index: Element index.

Returns an indexed property or array element as a Napi::Value.