fix(napi-derive-backend): Option value should produce optional types

examples/napi/index.d.ts

@@ -7,7 +7,7 @@ export function bigintAdd(a: BigInt, b: BigInt): BigInt
 export function createBigInt(): BigInt
 export function createBigIntI64(): BigInt
 export function getCwd(callback: (arg0: string) => void): void
-export function readFile(callback: (arg0: Error | undefined, arg1: string | null) => void): void
+export function readFile(callback: (arg0: Error | undefined, arg1?: string | undefined | null) => void): void
 export function eitherStringOrNumber(input: string | number): number
 export function returnEither(input: number): string | number
 export function either3(input: string | number | boolean): number
@@ -19,7 +19,7 @@ export enum Kind { Dog = 0, Cat = 1, Duck = 2 }
 export enum CustomNumEnum { One = 1, Two = 2, Three = 3, Four = 4, Six = 6, Eight = 8, Nine = 9, Ten = 10 }
 export function enumToI32(e: CustomNumEnum): number
 export function throwError(): void
-export function mapOption(val: number | null): number | null
+export function mapOption(val?: number | undefined | null): number | undefined | null
 export function add(a: number, b: number): number
 export function fibonacci(n: number): number
 export function listObjKeys(obj: object): Array<string>
@@ -31,8 +31,8 @@ export function asyncPlus100(p: Promise<number>): Promise<number>
 interface PackageJson {
   name: string
   version: string
-  dependencies: Record<string, any> | null
-  devDependencies: Record<string, any> | null
+  dependencies?: Record<string, any> | undefined | null
+  devDependencies?: Record<string, any> | undefined | null
 }
 export function readPackageJson(): PackageJson
 export function getPackageJsonName(packageJson: PackageJson): string
@@ -64,7 +64,7 @@ export class Blake2BKey {
   
 }
 export class Context {
-  
+  maybeNeed?: boolean | undefined | null
   constructor()
   static withData(data: string): Context
   method(): string

examples/napi/src/class.rs

@@ -79,6 +79,7 @@ impl Blake2bKey {
 #[napi]
 pub struct Context {
   data: String,
+  pub maybe_need: Option<bool>,
 }
 
 // Test for return `napi::Result` and `Result`
@@ -88,12 +89,16 @@ impl Context {
   pub fn new() -> napi::Result<Self> {
     Ok(Self {
       data: "not empty".into(),
+      maybe_need: None,
     })
   }
 
   #[napi(factory)]
   pub fn with_data(data: String) -> Result<Self> {
-    Ok(Self { data })
+    Ok(Self {
+      data,
+      maybe_need: Some(true),
+    })
   }
 
   #[napi]