feat(cli): support generation of literal union from string enum (#2054)

* feat(cli): support generation of literal union from enum

* Remove const

---------

Co-authored-by: LongYinan <lynweklm@gmail.com>

cli/src/utils/typegen.ts

@@ -10,6 +10,7 @@ export const DEFAULT_TYPE_DEF_HEADER = `/* auto-generated by NAPI-RS */
 enum TypeDefKind {
   Const = 'const',
   Enum = 'enum',
+  StringEnum = 'string_enum',
   Interface = 'interface',
   Fn = 'fn',
   Struct = 'struct',
@@ -41,6 +42,14 @@ function prettyPrint(
       s += `export ${enumName} ${line.name} {\n${line.def}\n}`
       break
 
+    case TypeDefKind.StringEnum:
+      if (constEnum) {
+        s += `export const enum ${line.name} {\n${line.def}\n}`
+      } else {
+        s += `export type ${line.name} = ${line.def.replaceAll(/.*=/g, '').replaceAll(',', '|')};`
+      }
+      break
+
     case TypeDefKind.Struct:
       s += `export class ${line.name} {\n${line.def}\n}`
       if (line.original_name && line.original_name !== line.name) {
@@ -75,6 +84,7 @@ export async function processTypeDef(
           switch (def.kind) {
             case TypeDefKind.Const:
             case TypeDefKind.Enum:
+            case TypeDefKind.StringEnum:
             case TypeDefKind.Fn:
             case TypeDefKind.Struct: {
               exports.push(def.name)

crates/backend/src/ast.rs

@@ -136,6 +136,7 @@ pub struct NapiEnum {
   pub comments: Vec<String>,
   pub skip_typescript: bool,
   pub register_name: Ident,
+  pub is_string_enum: bool,
 }
 
 #[derive(Debug, Clone)]

crates/backend/src/typegen/enum.rs

@@ -10,7 +10,11 @@ impl ToTypeDef for NapiEnum {
     add_alias(self.name.to_string(), self.js_name.to_string());
 
     Some(TypeDef {
-      kind: "enum".to_owned(),
+      kind: if self.is_string_enum {
+        "string_enum".to_owned()
+      } else {
+        "enum".to_owned()
+      },
       name: self.js_name.to_owned(),
       original_name: Some(self.name.to_string()),
       def: self.gen_ts_variants(),

crates/macro/src/parser/mod.rs

@@ -1070,6 +1070,7 @@ impl ConvertToAST for syn::ItemEnum {
       .js_name()
       .map_or_else(|| self.ident.to_string(), |(s, _)| s.to_string());
 
+    let is_string_enum = opts.string_enum().is_some();
     let variants = match opts.string_enum() {
       Some(case) => {
         let case = case.map(|c| Ok::<Case, Diagnostic>(match c.0.as_str() {
@@ -1183,6 +1184,7 @@ impl ConvertToAST for syn::ItemEnum {
         comments: extract_doc_comments(&self.attrs),
         skip_typescript: opts.skip_typescript().is_some(),
         register_name: get_register_ident(self.ident.to_string().as_str()),
+        is_string_enum,
       }),
     })
   }