fix(node): exclude internal events from public union

nodejs/test/session-event-codegen.test.ts

@@ -5,8 +5,59 @@ import { generateSessionEventsCode as generateCSharpSessionEventsCode } from "..
 import { generateGoSessionEventsCode } from "../../scripts/codegen/go.ts";
 import { generatePythonSessionEventsCode } from "../../scripts/codegen/python.ts";
 import { generateSessionEventsCode as generateRustSessionEventsCode } from "../../scripts/codegen/rust.ts";
+import { generateTypeScriptSessionEventsCode } from "../../scripts/codegen/typescript.ts";
 
 describe("session event codegen", () => {
+    it("excludes internal event wrappers from the public TypeScript union", async () => {
+        const schema: JSONSchema7 = {
+            definitions: {
+                SessionEvent: {
+                    anyOf: [
+                        { $ref: "#/definitions/PublicEvent" },
+                        { $ref: "#/definitions/InternalEvent" },
+                    ],
+                },
+                PublicEvent: {
+                    type: "object",
+                    required: ["type", "data"],
+                    properties: {
+                        type: { const: "session.public" },
+                        data: { $ref: "#/definitions/PublicData" },
+                    },
+                },
+                PublicData: {
+                    type: "object",
+                    required: ["message"],
+                    properties: {
+                        message: { type: "string" },
+                    },
+                },
+                InternalEvent: {
+                    type: "object",
+                    visibility: "internal",
+                    required: ["type", "data"],
+                    properties: {
+                        type: { const: "session.internal" },
+                        data: { $ref: "#/definitions/InternalData" },
+                    },
+                },
+                InternalData: {
+                    type: "object",
+                    required: ["attempt"],
+                    properties: {
+                        attempt: { type: "number" },
+                    },
+                },
+            },
+        };
+
+        const code = await generateTypeScriptSessionEventsCode(schema);
+
+        expect(code).toContain("export interface PublicEvent");
+        expect(code).not.toContain("InternalEvent");
+        expect(code).not.toContain("InternalData");
+    });
+
     it("maps special schema formats to the expected Python types", () => {
         const schema: JSONSchema7 = {
             definitions: {

scripts/codegen/typescript.ts

@@ -338,11 +338,7 @@ export function normalizeSchemaForTypeScript(schema: JSONSchema7): JSONSchema7 {
 
 // ── Session Events ──────────────────────────────────────────────────────────
 
-async function generateSessionEvents(schemaPath?: string): Promise<void> {
-    console.log("TypeScript: generating session-events...");
-
-    const resolvedPath = schemaPath ?? (await getSessionEventsSchemaPath());
-    const schema = (await loadSchemaJson(resolvedPath)) as JSONSchema7;
+export async function generateTypeScriptSessionEventsCode(schema: JSONSchema7): Promise<string> {
     const processed = propagateInternalVisibility(postProcessSchema(schema));
     const definitionCollections = collectDefinitionCollections(processed as Record<string, unknown>);
     const sessionEvent =
@@ -355,7 +351,7 @@ async function generateSessionEvents(schemaPath?: string): Promise<void> {
         const resolvedVariant = resolveSchema(variantSchema, definitionCollections) ?? variantSchema;
         const dataSchema = resolvedVariant.properties?.data as JSONSchema7 | undefined;
         const resolvedData = dataSchema ? resolveSchema(dataSchema, definitionCollections) ?? dataSchema : undefined;
-        if (!isSchemaInternal(resolvedData)) {
+        if (!isSchemaInternal(resolvedVariant) && !isSchemaInternal(resolvedData)) {
             return true;
         }
 
@@ -415,6 +411,15 @@ async function generateSessionEvents(schemaPath?: string): Promise<void> {
             `$1/** @internal */\n$2`
         );
     }
+    return annotatedTs;
+}
+
+async function generateSessionEvents(schemaPath?: string): Promise<void> {
+    console.log("TypeScript: generating session-events...");
+
+    const resolvedPath = schemaPath ?? (await getSessionEventsSchemaPath());
+    const schema = (await loadSchemaJson(resolvedPath)) as JSONSchema7;
+    const annotatedTs = await generateTypeScriptSessionEventsCode(schema);
     const outPath = await writeGeneratedFile("nodejs/src/generated/session-events.ts", annotatedTs);
     console.log(`  ✓ ${outPath}`);
 }