native buffer no need to keep raw napi pointer

examples/napi/__test__/typegen.spec.ts.md

@@ -11,7 +11,7 @@ Generated by [AVA](https://avajs.dev).
     `export function getWords(): Array<string>␊
     export function getNums(): Array<number>␊
     export function sumNums(nums: Array<number>): number␊
-    export function readFileAsync(path: string): Promise<Array<number>>␊
+    export function readFileAsync(path: string): Promise<Buffer>␊
     export function getCwd(callback: (arg0: string) => void): void␊
     export function readFile(callback: (arg0: Error | undefined, arg1: string | null) => void): void␊
     export enum Kind { Dog = 0, Cat = 1, Duck = 2 }␊

examples/napi/index.d.ts

@@ -1,7 +1,7 @@
 export function getWords(): Array<string>
 export function getNums(): Array<number>
 export function sumNums(nums: Array<number>): number
-export function readFileAsync(path: string): Promise<Array<number>>
+export function readFileAsync(path: string): Promise<Buffer>
 export function getCwd(callback: (arg0: string) => void): void
 export function readFile(callback: (arg0: Error | undefined, arg1: string | null) => void): void
 export enum Kind { Dog = 0, Cat = 1, Duck = 2 }

examples/napi/src/async.rs

@@ -3,15 +3,14 @@ use napi::bindgen_prelude::*;
 use tokio::fs;
 
 #[napi]
-async fn read_file_async(path: String) -> Result<Vec<u8>> {
+async fn read_file_async(path: String) -> Result<Buffer> {
   fs::read(path)
-    .map(|v| {
-      v.map_err(|e| {
-        Error::new(
-          Status::GenericFailure,
-          format!("failed to read file, {}", e),
-        )
-      })
+    .map(|r| match r {
+      Ok(content) => Ok(content.into()),
+      Err(e) => Err(Error::new(
+        Status::GenericFailure,
+        format!("failed to read file, {}", e),
+      )),
     })
     .await
 }