---
openproject: 365
---
# Task: OpenAPI 3.1 TypeScript Generation Support

## Related Documents
- Analysis: `docs/analysis/feature-enhancements-analysis.md` (Feature 2)
- OpenProject: [#365](https://pm.hyperlocalplatform.com/work_packages/365)
- Branch: `feature/365-openapi-31-support` (from `dev`)

## Priority
NORMAL

## Objective
Enhance TypeScript generation to properly handle OpenAPI 3.1-specific JSON Schema features. While parsing already works via swagger-parser, the `generate-types` tool doesn't handle 3.1's array types, `const` keyword, or webhook extraction.

## Definition of Done
- [x] Code implemented per specification
- [x] TypeScript compilation CLEAN
- [x] Lint checks PASSED (no lint script configured)
- [x] ALL tests passing (12/12)
- [x] Manual verification completed
- [x] PROOF PROVIDED

## Scope

### IN SCOPE
- Handle `type` as array: `type: ['string', 'null']` → `string | null`
- Handle `const` keyword: `const: "value"` → literal type `'value'`
- Extract `webhooks` count in metadata
- Display webhook count in formatted output
- Test fixture with OpenAPI 3.1 spec

### OUT OF SCOPE
- Full JSON Schema 2020-12 support (only common features)
- `$ref` with sibling properties (complex edge case)
- `pathItems` in components (rarely used)
- Batch operations (separate feature)

## Sub-Tasks

### Phase 1: Type Array Handling
#### 1.1 Update schemaToType() for array types
- **Details**: Detect when `type` is an array and map each type, joining with `|`
- **Files**: `src/tools/generate.ts`
- **Code**:
  ```typescript
  if (Array.isArray(s.type)) {
    return s.type.map(t => t === 'null' ? 'null' : mapPrimitiveType(t)).join(' | ');
  }
  ```
- **Testing**: Generate types from spec with `type: ['string', 'null']`

#### 1.2 Handle nullable migration
- **Details**: OpenAPI 3.1 replaces `nullable: true` with `type: ['T', 'null']`
- **Files**: `src/tools/generate.ts`
- **Testing**: Both 3.0 `nullable` and 3.1 array types produce `T | null`

### Phase 2: Const Keyword Support
#### 2.1 Implement const type generation
- **Details**: When `const` is present, output a literal type
- **Files**: `src/tools/generate.ts`
- **Code**:
  ```typescript
  if (s.const !== undefined) {
    return typeof s.const === 'string' ? `'${s.const}'` : String(s.const);
  }
  ```
- **Testing**: Schema with `const: "active"` generates `'active'`

### Phase 3: Webhook Metadata Extraction
#### 3.1 Add webhookCount to ParsedSpec
- **Details**: Add optional `webhookCount` field to ParsedSpec interface
- **Files**: `src/lib/types.ts`
- **Testing**: Type compiles

#### 3.2 Extract webhooks in parseSpec()
- **Details**: Count webhooks from `spec.webhooks` if present
- **Files**: `src/lib/parser.ts`
- **Code**:
  ```typescript
  webhookCount: spec.webhooks ? Object.keys(spec.webhooks).length : undefined
  ```
- **Testing**: Parse 3.1 spec with webhooks, verify count

#### 3.3 Display webhook count in formatted output
- **Details**: Show webhook count in human-readable output when present
- **Files**: `src/utils/format.ts`
- **Testing**: Format output includes "Webhooks: N"

### Phase 4: Testing
#### 4.1 Create OpenAPI 3.1 test fixture
- **Details**: Create a 3.1 spec with array types, const, and webhooks
- **Files**: `test/fixtures/openapi-31.yaml` (NEW)
- **Testing**: Fixture parses successfully

#### 4.2 Add unit tests for 3.1 features
- **Details**: Test type generation for all new features
- **Files**: `scripts/self-testing/openapi-31-test.ts` (NEW)
- **Testing**: All tests pass

#### 4.3 Verify backward compatibility
- **Details**: Ensure existing 3.0 and 2.0 specs still work
- **Files**: Existing test fixtures
- **Testing**: No regression in existing functionality

## Files to Modify

| File | Change |
|------|--------|
| `src/tools/generate.ts` | Handle array types, const keyword |
| `src/lib/types.ts` | Add `webhookCount?: number` to ParsedSpec |
| `src/lib/parser.ts` | Extract webhook count from spec |
| `src/utils/format.ts` | Display webhook count |
| `test/fixtures/openapi-31.yaml` | NEW: 3.1 test fixture |
| `scripts/self-testing/openapi-31-test.ts` | NEW: Unit tests |

## Risks & Mitigations

| Risk | Impact | Mitigation |
|------|--------|------------|
| Complex array type combinations | LOW | Map each type individually, join with `\|` |
| `const` with complex objects | LOW | Use JSON.stringify for non-primitives |
| Breaking existing 3.0 specs | LOW | Changes are additive, test backward compat |
| Type guard complexity for 3.1 detection | LOW | Use existing `isOpenAPI31()` guard |

## Testing Strategy
- Build: `npm run build` - must pass
- Lint: `npm run lint` - must pass
- Unit tests: `npx tsx scripts/self-testing/openapi-31-test.ts`
- Manual: Generate types from 3.1 spec, verify output

## Implementation Notes
- The `isOpenAPI31()` type guard already exists in `src/lib/spec-guards.ts`
- swagger-parser v10.1.1 already parses 3.1 specs correctly
- Changes should be additive - don't break 3.0/2.0 compatibility
- For const with objects, use `typeof value === 'object' ? 'object' : ...`