Schema with default: null becomes default("null") in generated Zod code

[robogeek]

Bug description

An OpenAPI schema with default: null becomes default("null") in generated Zod code

For full information see: fabien0102/openapi-codegen#212

Input

  /**
   * Long name of program for human readability.
   *
   * @example Residential Time of Use-A
   * @default null
   */
  programLongName?: string | null;
  /**
   * Short name of energy retailer providing the program.
   *
   * @example ACME
   * @default null
   */
  retailerName?: string | null;

Expected output

programLongName: z.string().optional().nullable().default(null),
  retailerName: z.string().optional().nullable().default(null),

Actual output

programLongName: z.string().optional().nullable().default("null"),
  retailerName: z.string().optional().nullable().default("null"),

Versions

• Typescript: v4.5.3
• Zod: v3.22.4

[schiller-manuel]

null is currently not handled in the @default JSDoc parsing, see https://github.com/fabien0102/ts-to-zod/blob/main/src/core/jsDocTags.ts#L177

[tvillaren]

It would make sense to handle it, wouldn't it?

[schiller-manuel]

It would make sense to handle it, wouldn't it?

sure!
Ideally we would also validate the @default value, i.e. only accept null if the type is actually nullable.

[tvillaren]

Or set it to nullable if it detects null as a default.

This would be consistent with the already implemented behaviour of removing the question mark when a property has a default:

ts-to-zod/src/utils/resolveDefaultProperties.ts

Lines 18 to 42 in 7c0835b

	const removeOptionalTransformer: ts.TransformerFactory<ts.SourceFile> = (
	context
	) => {
	const visit: ts.Visitor = (node) => {
	node = ts.visitEachChild(node, visit, context);
	if (ts.isPropertySignature(node)) {
	const jsDocTags = getJSDocTags(node, sourceFile);
	if (jsDocTags.default !== undefined) {
	const type = node.type
	? ts.visitEachChild(node.type, omitUndefinedKeyword, context)
	: undefined;
	return ts.factory.createPropertySignature(
	node.modifiers,
	node.name,
	undefined, // Remove `questionToken`
	type
	);
	}
	}
	return node;
	};
	return (node) => ts.visitNode(node, visit) as ts.SourceFile;
	};