napi wrap

napi_status napi_wrap(napi_env env,
                      napi_value js_object,
                      void* native_object,
                      napi_finalize finalize_cb,
                      void* finalize_hint,
                      napi_ref* result);

• [in] env: The environment that the API is invoked under.
• [in] js_object: The JavaScript object that will be the wrapper for the native object.
• [in] native_object: The native instance that will be wrapped in the JavaScript object.
• [in] finalize_cb: Optional native callback that can be used to free the native instance when the JavaScript object is ready for garbage-collection. [napi_finalize][] provides more details.
• [in] finalize_hint: Optional contextual hint that is passed to the finalize callback.
• [out] result: Optional reference to the wrapped object.

Returns napi_ok if the API succeeded.

Wraps a native instance in a JavaScript object. The native instance can be retrieved later using napi_unwrap().

When JavaScript code invokes a constructor for a class that was defined using napi_define_class(), the napi_callback for the constructor is invoked. After constructing an instance of the native class, the callback must then call napi_wrap() to wrap the newly constructed instance in the already-created JavaScript object that is the this argument to the constructor callback. (That this object was created from the constructor function’s prototype, so it already has definitions of all the instance properties and methods.)

Typically when wrapping a class instance, a finalize callback should be provided that simply deletes the native instance that is received as the data argument to the finalize callback.

The optional returned reference is initially a weak reference, meaning it has a reference count of 0. Typically this reference count would be incremented temporarily during async operations that require the instance to remain valid.

Caution: The optional returned reference (if obtained) should be deleted via [napi_delete_reference][] ONLY in response to the finalize callback invocation. If it is deleted before then, then the finalize callback may never be invoked. Therefore, when obtaining a reference a finalize callback is also required in order to enable correct disposal of the reference.

Calling napi_wrap() a second time on an object will return an error. To associate another native instance with the object, use napi_remove_wrap() first.