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Reference (template)

Holds a counted reference to a Napi::Value object; initially a weak reference unless otherwise specified, may be changed to/from a strong reference by adjusting the refcount.

The referenced Napi::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 Napi::Value.

Napi::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its destructor, running at program shutdown time, from attempting to reset the reference when the environment is no longer valid. Avoid using this if at all possible.

The following classes inherit, either directly or indirectly, from Napi::Reference:

Methods

Factory Method

static Napi::Reference<T> Napi::Reference::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

Napi::Reference::Reference();

Creates a new empty Napi::Reference instance.

Constructor

Napi::Reference::Reference(napi_env env, napi_value value);

  • [in] env: The napi_env environment in which to construct the Napi::Reference object.

  • [in] value: The Node-API primitive value to be held by the Napi::Reference.

Env

Napi::Env Napi::Reference::Env() const;

Returns the Napi::Env value in which the Napi::Reference was instantiated.

IsEmpty

bool Napi::Reference::IsEmpty() const;

Determines whether the value held by the Napi::Reference is empty.

Value

T Napi::Reference::Value() const;

Returns the value held by the Napi::Reference.

Ref

uint32_t Napi::Reference::Ref() const;

Increments the reference count for the Napi::Reference and returns the resulting reference count. Throws an error if the increment fails.

Unref

uint32_t Napi::Reference::Unref() const;

Decrements the reference count for the Napi::Reference and returns the resulting reference count. Throws an error if the decrement fails.

Reset (Empty)

void Napi::Reference::Reset();

Sets the value held by the Napi::Reference to be empty.

Reset

void Napi::Reference::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 Napi::Reference.

SuppressDestruct

void Napi::Reference::SuppressDestruct();

Call this method on a Napi::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.

Avoid using this if at all possible. If you do need to use static data, MAKE SURE to warn your users that your addon is NOT threadsafe.