Struct JsRc

pub struct JsRc<T: NapiRaw> { /* private fields */ }

Reference counter for JavaScript values.

Moves ownership of a JavaScript value to the Rust addon, preventing Nodejs’s GC from dropping the value.

The value will be dropped when the reference count goes to 0

Usage:

From Napi Function Argument

use napi::*;
use napi_derive::napi;
use napi_async_local::JsRc;

#[napi]
fn my_js_func(env: Env, callback: JsRc<JsFunction>) -> napi::Result<()> {
  let inner = callback.inner(&env)?;
  inner.call_without_args(None);
  Ok(())
}

Apply to Existing Value

Simplified with super::JsRcExt

use napi::*;
use napi_derive::napi;
use napi_async_local::JsRc;
use napi_async_local::UtilsExt;

#[napi]
fn my_js_func(env: Env) -> napi::Result<()> {
  let value = env.create_string("hello world")?;
  let value_ref = JsRc::new(value)?;
  let inner = value_ref.inner(&env)?;
   
  env.console_log(&[inner])?; // From UtilsExt
  Ok(())
}

Apply to Existing Value super::JsRcExt

use napi::*;
use napi_derive::napi;
use napi_async_local::JsRcExt;
use napi_async_local::UtilsExt;

#[napi]
fn my_js_func(env: Env) -> napi::Result<()> {
  let value = env.create_string("hello world")?;
  let value_ref = value.into_rc(&env)?; // From JsRcExt
  let inner = value_ref.inner(&env)?;
   
  env.console_log(&[inner])?; // From UtilsExt
  Ok(())
}

Implementations

impl<T: NapiValue> JsRc<T>

pub fn new(env: &Env, value: T) -> Result<Self>

pub fn inner<'a>(&self, env: &'a Env) -> Result<JsRcRef<'a, T>>

Obtain a reference to the inner JavaScript value

pub fn into_inner(&self, env: &Env) -> Result<T>

Trait Implementations

impl<T: NapiRaw> Clone for JsRc<T>

fn clone(&self) -> Self

Clone the container and increment the reference count by 1

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl<T: NapiRaw> Drop for JsRc<T>

fn drop(&mut self)

Executes the destructor for this type.

impl<T: NapiValue> FromNapiValue for JsRc<T>

unsafe fn from_napi_value(env: napi_env, napi_val: napi_value) -> Result<Self>

Safety

fn from_unknown(value: JsUnknown) -> Result<Self, Error>