napi-rs/examples/napi/src/callback.rs

use std::env;

use napi::bindgen_prelude::*;

#[napi]
fn get_cwd<T: Fn(String) -> Result<()>>(callback: T) {
  callback(env::current_dir().unwrap().to_string_lossy().to_string()).unwrap();
}

#[napi]
fn option_end<T: Fn(String, Option<String>) -> Result<()>>(callback: T) {
  callback("Hello".to_string(), None).unwrap();
}

#[napi]
fn option_start<T: Fn(Option<String>, String) -> Result<()>>(callback: T) {
  callback(None, "World".to_string()).unwrap();
}

#[napi]
fn option_start_end<T: Fn(Option<String>, String, Option<String>) -> Result<()>>(callback: T) {
  callback(None, "World".to_string(), None).unwrap();
}

#[napi]
fn option_only<T: Fn(Option<String>) -> Result<()>>(callback: T) {
  callback(None).unwrap();
}

/// napi = { version = 2, features = ["serde-json"] }
#[napi]
fn read_file<T: Fn(Result<()>, Option<String>) -> Result<()>>(callback: T) {
  match read_file_content() {
    Ok(s) => callback(Ok(()), Some(s)),
    Err(e) => callback(Err(e), None),
  }
  .unwrap();
}

fn read_file_content() -> Result<String> {
  // serde_json::from_str(&s)?;
  Ok("hello world".to_string())
}

#[napi]
fn return_js_function() -> Result<JsFunction> {
  get_js_function(read_file_js_function)
}