napi-rs/examples/napi-compat-mode/src/arraybuffer.rs

use std::f64::consts::PI;
use std::str;

use napi::{
  bindgen_prelude::Uint8Array, CallContext, JsArrayBuffer, JsNumber, JsObject, JsTypedArray,
  JsUndefined, Result,
};

#[js_function(1)]
pub fn get_arraybuffer_length(ctx: CallContext) -> Result<JsNumber> {
  let buffer = ctx.get::<JsArrayBuffer>(0)?.into_value()?;
  ctx.env.create_uint32(buffer.len() as u32)
}

#[js_function(1)]
pub fn mutate_uint8_array(ctx: CallContext) -> Result<JsUndefined> {
  let mut buffer = ctx.get::<Uint8Array>(0)?;
  let buffer_mut_ref: &mut [u8] = buffer.as_mut();
  buffer_mut_ref[0] = 42;
  ctx.env.get_undefined()
}

#[js_function(1)]
pub fn mutate_uint16_array(ctx: CallContext) -> Result<JsUndefined> {
  let mut buffer = ctx.get::<JsTypedArray>(0)?.into_value()?;
  let buffer_mut_ref: &mut [u16] = buffer.as_mut();
  buffer_mut_ref[0] = 65535;
  ctx.env.get_undefined()
}

#[js_function(1)]
pub fn mutate_int16_array(ctx: CallContext) -> Result<JsUndefined> {
  let mut buffer = ctx.get::<JsTypedArray>(0)?.into_value()?;
  let buffer_mut_ref: &mut [i16] = buffer.as_mut();
  buffer_mut_ref[0] = 32767;
  ctx.env.get_undefined()
}

#[js_function(1)]
pub fn mutate_float32_array(ctx: CallContext) -> Result<JsUndefined> {
  let mut buffer = ctx.get::<JsTypedArray>(0)?.into_value()?;
  let buffer_mut_ref: &mut [f32] = buffer.as_mut();
  buffer_mut_ref[0] = 3.33;
  ctx.env.get_undefined()
}

#[js_function(1)]
pub fn mutate_float64_array(ctx: CallContext) -> Result<JsUndefined> {
  let mut buffer = ctx.get::<JsTypedArray>(0)?.into_value()?;
  let buffer_mut_ref: &mut [f64] = buffer.as_mut();
  buffer_mut_ref[0] = PI;
  ctx.env.get_undefined()
}

#[js_function(1)]
#[cfg(feature = "latest")]
pub fn mutate_i64_array(ctx: CallContext) -> Result<JsUndefined> {
  let mut buffer = ctx.get::<JsTypedArray>(0)?.into_value()?;
  let buffer_mut_ref: &mut [i64] = buffer.as_mut();
  buffer_mut_ref[0] = 9223372036854775807;
  ctx.env.get_undefined()
}

pub fn register_js(exports: &mut JsObject) -> Result<()> {
  exports.create_named_method("getArraybufferLength", get_arraybuffer_length)?;
  exports.create_named_method("mutateUint8Array", mutate_uint8_array)?;
  exports.create_named_method("mutateUint16Array", mutate_uint16_array)?;
  exports.create_named_method("mutateInt16Array", mutate_int16_array)?;
  exports.create_named_method("mutateFloat32Array", mutate_float32_array)?;
  exports.create_named_method("mutateFloat64Array", mutate_float64_array)?;
  #[cfg(feature = "latest")]
  exports.create_named_method("mutateI64Array", mutate_i64_array)?;
  Ok(())
}