fix: improve typescript generator

package.json

@@ -8,7 +8,7 @@
   "bugs": "https://github.com/the-codegen-project/cli/issues",
   "dependencies": {
     "@asyncapi/avro-schema-parser": "^3.0.24",
-    "@asyncapi/modelina": "^6.0.0-next.7",
+    "@asyncapi/modelina": "^6.0.0-next.8",
     "@asyncapi/openapi-schema-parser": "^3.0.24",
     "@asyncapi/parser": "^3.4.0",
     "@asyncapi/protobuf-schema-parser": "^3.5.1",

src/codegen/modelina/presets/primitives.ts

@@ -4,7 +4,9 @@ import {
   ConstrainedIntegerModel,
   ConstrainedFloatModel,
   ConstrainedBooleanModel,
-  ConstrainedArrayModel
+  ConstrainedArrayModel,
+  ConstrainedAnyModel,
+  ConstrainedUnionModel
 } from '@asyncapi/modelina';
 import {TypeScriptRenderer} from '@asyncapi/modelina/lib/types/generators/typescript/TypeScriptRenderer';
 import {
@@ -32,6 +34,55 @@ function isPrimitiveModel(model: ConstrainedMetaModel): boolean {
   );
 }
 
+/**
+ * Check if the model is a null type (ConstrainedAnyModel with type: null in schema)
+ * Modelina converts null types to ConstrainedAnyModel
+ */
+function isNullModel(model: ConstrainedMetaModel): boolean {
+  if (!(model instanceof ConstrainedAnyModel)) {
+    return false;
+  }
+  // Check if the original input schema has type: null
+  const originalInput = model.originalInput;
+  return originalInput && originalInput.type === 'null';
+}
+
+/**
+ * Check if the model is a date format string type (date or date-time)
+ * Note: 'time' format is NOT included because RFC 3339 time strings like "14:30:00"
+ * are not valid Date constructor arguments in JavaScript and would produce Invalid Date.
+ * Time values should remain as strings.
+ */
+function isDateFormatModel(model: ConstrainedMetaModel): boolean {
+  if (!(model instanceof ConstrainedStringModel)) {
+    return false;
+  }
+  const format = model.originalInput?.format;
+  return format === 'date' || format === 'date-time';
+}
+
+/**
+ * Render marshal function for null type
+ */
+function renderNullMarshal(model: ConstrainedMetaModel): string {
+  return `export function marshal(payload: null): string {
+  return JSON.stringify(payload);
+}`;
+}
+
+/**
+ * Render unmarshal function for null type
+ */
+function renderNullUnmarshal(model: ConstrainedMetaModel): string {
+  return `export function unmarshal(json: string): null {
+  const parsed = JSON.parse(json);
+  if (parsed !== null) {
+    throw new Error('Expected null value');
+  }
+  return null;
+}`;
+}
+
 /**
  * Render marshal function for primitive types
  */
@@ -52,6 +103,27 @@ function renderPrimitiveUnmarshal(model: ConstrainedMetaModel): string {
 }`;
 }
 
+/**
+ * Render unmarshal function for date format types
+ * Converts JSON string to JavaScript Date object
+ */
+function renderDateUnmarshal(model: ConstrainedMetaModel): string {
+  return `export function unmarshal(json: string): ${model.name} {
+  const parsed = JSON.parse(json);
+  return new Date(parsed);
+}`;
+}
+
+/**
+ * Render marshal function for date format types
+ * Note: JSON.stringify(Date) calls Date.toJSON() which returns ISO string
+ */
+function renderDateMarshal(model: ConstrainedMetaModel): string {
+  return `export function marshal(payload: ${model.name}): string {
+  return JSON.stringify(payload);
+}`;
+}
+
 /**
  * Render marshal function for array types
  */
@@ -86,11 +158,15 @@ function renderArrayMarshal(model: ConstrainedArrayModel): string {
 function renderArrayUnmarshal(model: ConstrainedArrayModel): string {
   const valueModel = model.valueModel;
 
-  // Check if array items have an unmarshal method (object types)
+  // Check if array items have an unmarshal method (only object types do)
+  // Exclude primitives, nested arrays, and union types - they don't have unmarshal methods
+  // Union types are just type aliases without static unmarshal methods
   const hasItemUnmarshal =
     valueModel.type !== 'string' &&
     valueModel.type !== 'number' &&
-    valueModel.type !== 'boolean';
+    valueModel.type !== 'boolean' &&
+    !(valueModel instanceof ConstrainedArrayModel) &&
+    !(valueModel instanceof ConstrainedUnionModel);
 
   if (hasItemUnmarshal) {
     const itemTypeName = valueModel.name;
@@ -145,10 +221,19 @@ export function createPrimitivesPreset(
       }) {
         // Handle primitive types (string, integer, float, boolean)
         if (isPrimitiveModel(model)) {
+          // Use date-specific marshal/unmarshal for date formats
+          const isDate = isDateFormatModel(model);
+          const unmarshalFunc = isDate
+            ? renderDateUnmarshal(model)
+            : renderPrimitiveUnmarshal(model);
+          const marshalFunc = isDate
+            ? renderDateMarshal(model)
+            : renderPrimitiveMarshal(model);
+
           return `${content}
 
-${renderPrimitiveUnmarshal(model)}
-${renderPrimitiveMarshal(model)}
+${unmarshalFunc}
+${marshalFunc}
 ${options.includeValidation ? generateTypescriptValidationCode({model, renderer, asClassMethods: false, context: context as any}) : ''}
 `;
         }
@@ -163,6 +248,16 @@ ${options.includeValidation ? generateTypescriptValidationCode({model, renderer,
 `;
         }
 
+        // Handle null types (ConstrainedAnyModel with type: null in original schema)
+        if (isNullModel(model)) {
+          return `${content}
+
+${renderNullUnmarshal(model)}
+${renderNullMarshal(model)}
+${options.includeValidation ? generateTypescriptValidationCode({model, renderer, asClassMethods: false, context: context as any}) : ''}
+`;
+        }
+
         return content;
       }
     }

src/codegen/modelina/presets/validation.ts

@@ -12,6 +12,7 @@ export function safeStringify(value: any): string {
   let depth = 0;
   const maxDepth = 255;
   const maxRepetitions = 5; // Allow up to 5 repetitions of the same object
+  let isRoot = true;
 
   // eslint-disable-next-line sonarjs/cognitive-complexity
   function stringify(val: any, currentPath: any[] = []): any {
@@ -50,13 +51,22 @@ export function safeStringify(value: any): string {
 
         depth++;
         const newPath = [...currentPath, val];
+        const atRoot = isRoot;
+        isRoot = false;
 
         let result: any;
 
         if (Array.isArray(val)) {
           result = val.map((item) => stringify(item, newPath));
         } else {
           result = {};
+          // Check if this is a root-level schema with oneOf/anyOf that has conflicting type:object
+          // Modelina adds type:object to union models, but this conflicts with primitive oneOf/anyOf
+          const hasCompositionKeyword =
+            val.oneOf !== undefined || val.anyOf !== undefined;
+          const hasConflictingObjectType =
+            val.type === 'object' && hasCompositionKeyword;
+
           for (const [key, value] of Object.entries(val)) {
             // Skip extension properties
             if (
@@ -68,6 +78,10 @@ export function safeStringify(value: any): string {
             ) {
               continue;
             }
+            // Skip type:object at root level when there's oneOf/anyOf with primitives
+            if (atRoot && key === 'type' && hasConflictingObjectType) {
+              continue;
+            }
             // eslint-disable-next-line security/detect-object-injection
             result[key] = stringify(value, newPath);
           }
@@ -128,6 +142,9 @@ export function generateTypescriptValidationCode({
   return `${schemaProperty} = ${safeStringify(model.originalInput)};
 ${methodPrefix}validate(context?: {data: any, ajvValidatorFunction?: ValidateFunction, ajvInstance?: Ajv, ajvOptions?: AjvOptions}): { valid: boolean; errors?: ErrorObject[]; } {
   const {data, ajvValidatorFunction} = context ?? {};
+  // Intentionally parse JSON strings to support validation of marshalled output.
+  // Example: validate({data: marshal(obj)}) works because marshal returns JSON string.
+  // Note: String 'true' will be coerced to boolean true due to JSON.parse.
   const parsedData = typeof data === 'string' ? JSON.parse(data) : data;
   const validate = ajvValidatorFunction ?? ${createValidatorCall}
   return {

test/codegen/configurations.spec.ts

@@ -60,13 +60,10 @@ describe('configuration manager', () => {
       const { config } = await loadAndRealizeConfigFile(CONFIG_YAML);
       expect(config.inputType).toEqual('asyncapi');
     });
-    /**
-     * Cannot run this in this Jest environment, had to manually test it. 
-     * 
-     * TODO
-     */
+    // TypeScript config files require ts-node/tsx for dynamic imports.
+    // This works at runtime (CLI with tsx), but Jest can't load TS files dynamically.
     // eslint-disable-next-line jest/no-disabled-tests
-    it.skip('should work with correct TS config', async () => {
+    it.skip('should work with correct TS config (requires ts-node/tsx runtime)', async () => {
       const { config } = await loadAndRealizeConfigFile(CONFIG_TS);
       expect(config.inputType).toEqual('asyncapi');
     });

test/codegen/generators/typescript/__snapshots__/headers.spec.ts.snap

@@ -1,4 +1,4 @@
-// Jest Snapshot v1, https://jestjs.io/docs/snapshot-testing
+// Jest Snapshot v1, https://goo.gl/fbAQLP
 
 exports[`headers typescript should work with OpenAPI 2.0 inputs 1`] = `
 "import {Ajv, Options as AjvOptions, ErrorObject, ValidateFunction} from 'ajv';
@@ -39,6 +39,9 @@ class DeletePetHeaders {
   public static theCodeGenSchema = {"type":"object","additionalProperties":false,"properties":{"api_key":{"type":"string"}},"$id":"DeletePetHeaders","$schema":"http://json-schema.org/draft-07/schema"};
   public static validate(context?: {data: any, ajvValidatorFunction?: ValidateFunction, ajvInstance?: Ajv, ajvOptions?: AjvOptions}): { valid: boolean; errors?: ErrorObject[]; } {
     const {data, ajvValidatorFunction} = context ?? {};
+    // Intentionally parse JSON strings to support validation of marshalled output.
+    // Example: validate({data: marshal(obj)}) works because marshal returns JSON string.
+    // Note: String 'true' will be coerced to boolean true due to JSON.parse.
     const parsedData = typeof data === 'string' ? JSON.parse(data) : data;
     const validate = ajvValidatorFunction ?? this.createValidator(context)
     return {
@@ -97,6 +100,9 @@ class DeletePetHeaders {
   public static theCodeGenSchema = {"type":"object","additionalProperties":false,"properties":{"api_key":{"type":"string"}},"$id":"DeletePetHeaders","$schema":"http://json-schema.org/draft-07/schema"};
   public static validate(context?: {data: any, ajvValidatorFunction?: ValidateFunction, ajvInstance?: Ajv, ajvOptions?: AjvOptions}): { valid: boolean; errors?: ErrorObject[]; } {
     const {data, ajvValidatorFunction} = context ?? {};
+    // Intentionally parse JSON strings to support validation of marshalled output.
+    // Example: validate({data: marshal(obj)}) works because marshal returns JSON string.
+    // Note: String 'true' will be coerced to boolean true due to JSON.parse.
     const parsedData = typeof data === 'string' ? JSON.parse(data) : data;
     const validate = ajvValidatorFunction ?? this.createValidator(context)
     return {
@@ -155,6 +161,9 @@ class DeletePetHeaders {
   public static theCodeGenSchema = {"type":"object","additionalProperties":false,"properties":{"api_key":{"type":"string"}},"$id":"DeletePetHeaders","$schema":"http://json-schema.org/draft-07/schema"};
   public static validate(context?: {data: any, ajvValidatorFunction?: ValidateFunction, ajvInstance?: Ajv, ajvOptions?: AjvOptions}): { valid: boolean; errors?: ErrorObject[]; } {
     const {data, ajvValidatorFunction} = context ?? {};
+    // Intentionally parse JSON strings to support validation of marshalled output.
+    // Example: validate({data: marshal(obj)}) works because marshal returns JSON string.
+    // Note: String 'true' will be coerced to boolean true due to JSON.parse.
     const parsedData = typeof data === 'string' ? JSON.parse(data) : data;
     const validate = ajvValidatorFunction ?? this.createValidator(context)
     return {
@@ -247,6 +256,9 @@ class SimpleObjectHeaders {
   public static theCodeGenSchema = {"type":"object","properties":{"displayName":{"type":"string","description":"Name of the user"},"email":{"type":"string","format":"email","description":"Email of the user"}},"$id":"SimpleObjectHeaders","$schema":"http://json-schema.org/draft-07/schema"};
   public static validate(context?: {data: any, ajvValidatorFunction?: ValidateFunction, ajvInstance?: Ajv, ajvOptions?: AjvOptions}): { valid: boolean; errors?: ErrorObject[]; } {
     const {data, ajvValidatorFunction} = context ?? {};
+    // Intentionally parse JSON strings to support validation of marshalled output.
+    // Example: validate({data: marshal(obj)}) works because marshal returns JSON string.
+    // Note: String 'true' will be coerced to boolean true due to JSON.parse.
     const parsedData = typeof data === 'string' ? JSON.parse(data) : data;
     const validate = ajvValidatorFunction ?? this.createValidator(context)
     return {

test/codegen/generators/typescript/__snapshots__/payload.spec.ts.snap

@@ -1,4 +1,4 @@
-// Jest Snapshot v1, https://jestjs.io/docs/snapshot-testing
+// Jest Snapshot v1, https://goo.gl/fbAQLP
 
 exports[`payloads typescript should not render validation functions 1`] = `
 "import {SimpleObject} from './SimpleObject';
@@ -116,9 +116,12 @@ return payload.marshal();
   return JSON.stringify(payload);
 }
 
-export const theCodeGenSchema = {"type":"object","$schema":"http://json-schema.org/draft-07/schema","oneOf":[{"type":"object","properties":{"type":{"const":"SimpleObject"},"displayName":{"type":"string","description":"Name of the user"},"email":{"type":"string","format":"email","description":"Email of the user"}},"$id":"SimpleObject"},{"type":"boolean","$id":"Boolean"},{"type":"string","$id":"String"}],"$id":"UnionPayload"};
+export const theCodeGenSchema = {"$schema":"http://json-schema.org/draft-07/schema","oneOf":[{"type":"object","properties":{"type":{"const":"SimpleObject"},"displayName":{"type":"string","description":"Name of the user"},"email":{"type":"string","format":"email","description":"Email of the user"}},"$id":"SimpleObject"},{"type":"boolean","$id":"Boolean"},{"type":"string","$id":"String"}],"$id":"UnionPayload"};
 export function validate(context?: {data: any, ajvValidatorFunction?: ValidateFunction, ajvInstance?: Ajv, ajvOptions?: AjvOptions}): { valid: boolean; errors?: ErrorObject[]; } {
   const {data, ajvValidatorFunction} = context ?? {};
+  // Intentionally parse JSON strings to support validation of marshalled output.
+  // Example: validate({data: marshal(obj)}) works because marshal returns JSON string.
+  // Note: String 'true' will be coerced to boolean true due to JSON.parse.
   const parsedData = typeof data === 'string' ? JSON.parse(data) : data;
   const validate = ajvValidatorFunction ?? createValidator(context)
   return {
@@ -205,6 +208,9 @@ class SimpleObject2 {
   public static theCodeGenSchema = {"type":"object","$schema":"http://json-schema.org/draft-07/schema","properties":{"displayName":{"type":"string","description":"Name of the user"},"email":{"type":"string","format":"email","description":"Email of the user"}},"$id":"SimpleObject2"};
   public static validate(context?: {data: any, ajvValidatorFunction?: ValidateFunction, ajvInstance?: Ajv, ajvOptions?: AjvOptions}): { valid: boolean; errors?: ErrorObject[]; } {
     const {data, ajvValidatorFunction} = context ?? {};
+    // Intentionally parse JSON strings to support validation of marshalled output.
+    // Example: validate({data: marshal(obj)}) works because marshal returns JSON string.
+    // Note: String 'true' will be coerced to boolean true due to JSON.parse.
     const parsedData = typeof data === 'string' ? JSON.parse(data) : data;
     const validate = ajvValidatorFunction ?? this.createValidator(context)
     return {
@@ -297,6 +303,9 @@ class SimpleObject {
   public static theCodeGenSchema = {"type":"object","$schema":"http://json-schema.org/draft-07/schema","properties":{"type":{"const":"SimpleObject"},"displayName":{"type":"string","description":"Name of the user"},"email":{"type":"string","format":"email","description":"Email of the user"}},"$id":"SimpleObject"};
   public static validate(context?: {data: any, ajvValidatorFunction?: ValidateFunction, ajvInstance?: Ajv, ajvOptions?: AjvOptions}): { valid: boolean; errors?: ErrorObject[]; } {
     const {data, ajvValidatorFunction} = context ?? {};
+    // Intentionally parse JSON strings to support validation of marshalled output.
+    // Example: validate({data: marshal(obj)}) works because marshal returns JSON string.
+    // Note: String 'true' will be coerced to boolean true due to JSON.parse.
     const parsedData = typeof data === 'string' ? JSON.parse(data) : data;
     const validate = ajvValidatorFunction ?? this.createValidator(context)
     return {