napi-rs/examples/napi/src/external.rs

use napi::bindgen_prelude::*;

#[napi]
pub fn create_external(size: u32) -> External<u32> {
  External::new(size)
}

#[napi]
pub fn create_external_string(content: String) -> External<String> {
  External::new(content)
}

#[napi]
pub fn get_external(external: &External<u32>) -> u32 {
  **external
}

#[napi]
pub fn mutate_external(external: &mut External<u32>, new_val: u32) {
  **external = new_val;
}

#[napi]
pub fn create_optional_external(size: Option<u32>) -> Option<External<u32>> {
  size.map(External::new)
}

#[napi]
pub fn get_optional_external(external: Option<&External<u32>>) -> Option<u32> {
  external.map(|external| **external)
}

#[napi]
pub fn mutate_optional_external(external: Option<&mut External<u32>>, new_val: u32) {
  if let Some(external) = external {
    **external = new_val;
  }
}