fix(codegen): generate string literal unions for Enums (#95)

lib/codegen/fromcto/rust/rustvisitor.js

@@ -304,6 +304,7 @@ class RustVisitor {
      * @private
      */
     visitClassDeclaration(classDeclaration, parameters) {
+        this.writeDescription(classDeclaration, parameters, 0);
         parameters.fileWriter.writeLine(
             0,
             '#[derive(Debug, Clone, Serialize, Deserialize)]'
@@ -513,6 +514,8 @@ class RustVisitor {
             if (field.isOptional?.()) {
                 hashMapType = this.wrapAsOption(hashMapType);
             }
+            // Add description for HashMap fields
+            this.writeDescription(field, parameters, 1);
 
             // Generate serde attributes for HashMap with DateTime serialization support
             parameters.fileWriter.writeLine(1, '#[serde(');
@@ -607,6 +610,10 @@ class RustVisitor {
         }
 
         // Handle regular (non-HashMap) fields
+
+        // Add description for regular fields
+        this.writeDescription(field, parameters, 1);
+
         parameters.fileWriter.writeLine(1, '#[serde(');
         parameters.fileWriter.writeLine(2, `rename = "${field.name}",`);
         if (field.isOptional?.()) {
@@ -752,6 +759,7 @@ class RustVisitor {
         if (relationshipDeclaration.isOptional?.()) {
             type = `Option<${type}>`;
         }
+        this.writeDescription(relationshipDeclaration, parameters, 1);
 
         // Start serde attribute block
         parameters.fileWriter.writeLine(1, '#[serde(');
@@ -1327,6 +1335,24 @@ class RustVisitor {
 
         parameters.fileWriter.closeFile();
     }
+    /**
+     * Writes the description of a declaration or property as a Rust documentation comment.
+     * @param {Object} thing - the declaration or property
+     * @param {Object} parameters - the parameters
+     * @param {number} indent - the indentation level
+     * @private
+     */
+    writeDescription(thing, parameters, indent) {
+        if (thing.getDescription && thing.getDescription()) {
+            const description = thing.getDescription();
+            // Split by newline to handle multi-line comments cleanly
+            const lines = description.split(/\r?\n/);
+            lines.forEach(line => {
+                // Write '/// ' followed by the trimmed line
+                parameters.fileWriter.writeLine(indent, `/// ${line.trim()}`);
+            });
+        }
+    }
 }
 
 module.exports = RustVisitor;

lib/codegen/fromcto/typescript/typescriptvisitor.js

@@ -184,17 +184,23 @@ class TypescriptVisitor {
      * @private
      */
     visitEnumDeclaration(enumDeclaration, parameters) {
+        const properties = enumDeclaration.getOwnProperties();
 
-        parameters.fileWriter.writeLine(0, 'export enum ' + enumDeclaration.getName() + ' {');
+        if (properties.length === 0) {
+            // Handle empty enums to ensure valid TypeScript syntax
+            parameters.fileWriter.writeLine(0, 'export type ' + enumDeclaration.getName() + ' = never;');
+        } else {
+            parameters.fileWriter.writeLine(0, 'export type ' + enumDeclaration.getName() + ' =');
+            const values = properties
+                .map(property => `'${property.getName()}'`)
+                .join(' | ');
 
-        enumDeclaration.getOwnProperties().forEach((property) => {
-            property.accept(this, parameters);
-        });
+            parameters.fileWriter.writeLine(1, values + ';');
+        }
 
-        parameters.fileWriter.writeLine(0, '}\n');
+        parameters.fileWriter.writeLine(0, '');
         return null;
     }
-
     /**
      * Visitor design pattern
      * @param {ClassDeclaration} classDeclaration - the object being visited
@@ -271,7 +277,8 @@ class TypescriptVisitor {
             const subclasses = field.getParent().getModelFile().getModelManager().getType(field.getFullyQualifiedTypeName()).getDirectSubclasses();
             if (subclasses && subclasses.length > 0) {
                 const useUnion = !(isEnumRef || isMapRef);
-                tsType = this.toTsType(field.getType(), !useUnion, useUnion);
+                const useInterface = !useUnion && !isEnumRef && !isMapRef;
+                tsType = this.toTsType(field.getType(), useInterface, useUnion);
             }
         }
 
@@ -400,4 +407,4 @@ class TypescriptVisitor {
     }
 }
 
-module.exports = TypescriptVisitor;
+module.exports = TypescriptVisitor;

test/codegen/fromcto/typescript/typescriptvisitor.js

@@ -442,7 +442,7 @@ describe('TypescriptVisitor', function () {
     });
 
     describe('visitEnumDeclaration', () => {
-        it('should write the export enum and call accept on each property', () => {
+        it('should write the export type and string union', () => {
             let acceptSpy = sinon.spy();
 
             let param = {
@@ -452,20 +452,22 @@ describe('TypescriptVisitor', function () {
             let mockEnumDeclaration = sinon.createStubInstance(EnumDeclaration);
             mockEnumDeclaration.isEnum.returns(true);
             mockEnumDeclaration.getName.returns('Bob');
+
             mockEnumDeclaration.getOwnProperties.returns([{
-                accept: acceptSpy
+                accept: acceptSpy,
+                getName: () => 'RED'
             },
             {
-                accept: acceptSpy
+                accept: acceptSpy,
+                getName: () => 'BLUE'
             }]);
 
             typescriptVisitor.visitEnumDeclaration(mockEnumDeclaration, param);
 
-            param.fileWriter.writeLine.callCount.should.deep.equal(2);
-            param.fileWriter.writeLine.withArgs(0, 'export enum Bob {').calledOnce.should.be.ok;
-            param.fileWriter.writeLine.withArgs(0, '}\n').calledOnce.should.be.ok;
-
-            acceptSpy.withArgs(typescriptVisitor, param).calledTwice.should.be.ok;
+            param.fileWriter.writeLine.callCount.should.deep.equal(3);
+            param.fileWriter.writeLine.withArgs(0, 'export type Bob =').calledOnce.should.be.ok;
+            param.fileWriter.writeLine.withArgs(1, '\'RED\' | \'BLUE\';').calledOnce.should.be.ok;
+            param.fileWriter.writeLine.withArgs(0, '').calledOnce.should.be.ok;
         });
     });