napi-rs/test_module/src/class.rs

use std::convert::TryInto;

use napi::{CallContext, JsFunction, JsNumber, JsObject, JsUndefined, Module, Property, Result};

#[js_function(1)]
fn create_test_class(ctx: CallContext) -> Result<JsFunction> {
  let add_count_method = Property::new("addCount").with_method(add_count);
  let mut properties = vec![add_count_method];
  ctx.env.define_class(
    "TestClass",
    test_class_constructor,
    properties.as_mut_slice(),
  )
}

#[js_function(1)]
fn test_class_constructor(mut ctx: CallContext<JsObject>) -> Result<JsUndefined> {
  let count = ctx.get::<JsNumber>(0)?;
  ctx
    .this
    .set_named_property("count", ctx.env.create_int32(count.try_into()?)?)?;
  ctx.env.get_undefined()
}

#[js_function(1)]
fn add_count(mut ctx: CallContext<JsObject>) -> Result<JsUndefined> {
  let add: i32 = ctx.get::<JsNumber>(0)?.try_into()?;
  let count: i32 = ctx
    .this
    .get_named_property::<JsNumber>("count")?
    .try_into()?;
  ctx
    .this
    .set_named_property("count", ctx.env.create_int32(count + add)?)?;
  ctx.env.get_undefined()
}

pub fn register_js(module: &mut Module) -> Result<()> {
  module.create_named_method("createTestClass", create_test_class)?;
  Ok(())
}