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fix: support arrow functions in OpenAPI generator - #1058
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When arrow functions that return codecs were
imported from a utils module, the OpenAPI generator would output empty
schemas ({}) instead of the correct type definitions.
Example that broke:
```typescript
// utils.ts
export const BooleanFromNullableWithFallback = () =>
fromNullable(t.union([BooleanFromString, t.boolean]), false);
// schema.ts
import { BooleanFromNullableWithFallback } from './utils';
const Wallet = t.type({
hasLargeNumberOfAddresses: BooleanFromNullableWithFallback() // INCORRECTLY Generates: {}
});
```
The generator couldn't resolve CallExpressions where the callee is an
arrow function. When it looked up the identifier and found an arrow
function, it had no logic to parse the function body, falling back to
an empty schema.
This fix:
- Adds parseFunctionBody() to extract and parse arrow function return values
- Detects when CallExpression callees resolve to arrow functions
- Uses findSymbolInitializer() for cross-file lookup of imported functions
Test covers the bug scenario: calling an arrow function factory
(BooleanFromNullableWithFallback()) within a codec property definition.
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🎉 This PR is included in version @api-ts/openapi-generator@5.10.3 🎉 The release is available on npm package (@latest dist-tag) Your semantic-release bot 📦🚀 |
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Ticket: DX-1799
Problem
The generator couldn't resolve
CallExpressionswhere the callee is an arrow function. When it looked upBooleanFromNullableWithFallbackand found an arrow function, it had no logic to parse the function body to extract the codec it returns, falling back to an empty schema.Example of the issue can be found in the ticket description.
Fix:
parseFunctionBody()to extract and parse arrow function return valuesCallExpressioncallees resolve to arrow functionsfindSymbolInitializer()for cross-file lookup of imported functionsexpression body (() => expr)Validation:
Test covers the bug scenario: calling an arrow function
BooleanFromNullableWithFallback()within a codec property definition.Note:
Block statement arrow functions were not part of the bug, but its valid TypeScript that the parser is not supporting.
An example of one is:
block statement (() => { return expr }).I added that in the error message and have created a new ticket DX-2182 to address this.