fix(openapi-typescript): type errors generated under enumValues (#1867)

* fix(openapi-typescript): type errors generated under `enumValues`

* Create proud-students-repeat.md

Author: phk422

.changeset/proud-students-repeat.md

@@ -0,0 +1,5 @@
+---
+"openapi-typescript": patch
+---
+
+fix(openapi-typescript): type errors generated under `enumValues`

packages/openapi-typescript/src/lib/ts.ts

@@ -242,13 +242,13 @@ export function tsArrayLiteralExpression(
   name: string,
   elementType: ts.TypeNode,
   values: (string | number)[],
-  options?: { export?: boolean; readonly?: boolean },
+  options?: { export?: boolean; readonly?: boolean; injectFooter?: ts.Node[] },
 ) {
   let variableName = sanitizeMemberName(name);
   variableName = `${variableName[0].toLowerCase()}${variableName.substring(1)}`;
 
   const arrayType = options?.readonly
-    ? ts.factory.createTypeReferenceNode("ReadonlyArray", [elementType])
+    ? tsReadonlyArray(elementType, options.injectFooter)
     : ts.factory.createArrayTypeNode(elementType);
 
   return ts.factory.createVariableStatement(
@@ -490,3 +490,21 @@ export function tsWithRequired(
     tsUnion(keys.map((k) => tsLiteral(k))),
   ]);
 }
+
+/**
+ * Enhanced ReadonlyArray.
+ * eg: type Foo = ReadonlyArray<T>; type Bar = ReadonlyArray<T[]>
+ * Foo and Bar are both of type `readonly T[]`
+ */
+export function tsReadonlyArray(type: ts.TypeNode, injectFooter?: ts.Node[]): ts.TypeNode {
+  if (
+    injectFooter &&
+    !injectFooter.some((node) => ts.isTypeAliasDeclaration(node) && node?.name?.escapedText === "ReadonlyArray")
+  ) {
+    const helper = stringToAST(
+      "type ReadonlyArray<T> = [Exclude<T, undefined>] extends [any[]] ? Readonly<Exclude<T, undefined>> : Readonly<Exclude<T, undefined>[]>;",
+    )[0] as any;
+    injectFooter.push(helper);
+  }
+  return ts.factory.createTypeReferenceNode(ts.factory.createIdentifier("ReadonlyArray"), [type]);
+}

packages/openapi-typescript/src/transform/schema-object.ts

@@ -136,6 +136,7 @@ export function transformSchemaObjectWithComposition(
         {
           export: true,
           readonly: true,
+          injectFooter: options.ctx.injectFooter,
         },
       );
 

packages/openapi-typescript/test/node-api.test.ts

@@ -797,6 +797,11 @@ export interface components {
     pathItems: never;
 }
 export type $defs = Record<string, never>;
+type ReadonlyArray<T> = [
+    Exclude<T, undefined>
+] extends [
+    any[]
+] ? Readonly<Exclude<T, undefined>> : Readonly<Exclude<T, undefined>[]>;
 export const pathsUrlGetParametersQueryStatusValues: ReadonlyArray<paths["/url"]["get"]["parameters"]["query"]["status"]> = ["active", "inactive"];
 export const statusValues: ReadonlyArray<components["schemas"]["Status"]> = ["active", "inactive"];
 export const errorCodeValues: ReadonlyArray<components["schemas"]["ErrorCode"]> = [100, 101, 102, 103, 104, 105];