handle unset unions

.changeset/witty-rings-do.md

@@ -0,0 +1,5 @@
+---
+"@smithy/smithy-client": minor
+---
+
+add quoteHeader function

packages/smithy-client/src/quote-header.spec.ts

@@ -0,0 +1,11 @@
+import { quoteHeader } from "./quote-header";
+
+describe(quoteHeader.name, () => {
+  it("should wrap header elements that include the delimiter", () => {
+    expect(quoteHeader("b,c")).toBe('"b,c"');
+  });
+
+  it("should not wrap header elements that don't include the delimiter", () => {
+    expect(quoteHeader("bc")).toBe("bc");
+  });
+});

packages/smithy-client/src/quote-header.ts

@@ -0,0 +1,8 @@
+/**
+ * @public
+ * @param part - header list element
+ * @returns quoted string if part contains delimiter.
+ */
+export function quoteHeader(part: string) {
+  return part.includes(",") ? `"${part}"` : part;
+}

smithy-typescript-codegen/src/main/java/software/amazon/smithy/typescript/codegen/HttpProtocolTestGenerator.java

@@ -545,9 +545,11 @@ private void writeHttpHostAssertion(HttpRequestTestCase testCase) {
     }
 
     private void writeHttpBodyAssertions(String body, String mediaType, boolean isClientTest) {
-        // If we expect an empty body, expect it to be falsy.
         if (body.isEmpty()) {
-            writer.write("expect(r.body).toBeFalsy();");
+            // If we expect an empty body, expect it to be falsy.
+            // Or, for JSON an empty object represents an empty body.
+            // mediaType is often UNKNOWN here.
+            writer.write("expect(!r.body || r.body === `{}`).toBeTruthy();");
             return;
         }
 

smithy-typescript-codegen/src/main/java/software/amazon/smithy/typescript/codegen/integration/HttpBindingProtocolGenerator.java

@@ -16,6 +16,7 @@
 package software.amazon.smithy.typescript.codegen.integration;
 
 import java.nio.file.Paths;
+import java.sql.Types;
 import java.util.Collection;
 import java.util.Collections;
 import java.util.Comparator;
@@ -1385,7 +1386,8 @@ private String getCollectionInputParam(
 
         switch (bindingType) {
             case HEADER:
-                return iteratedParam + ".join(', ')";
+                context.getWriter().addImport("quoteHeader", "__quoteHeader", TypeScriptDependency.AWS_SMITHY_CLIENT);
+                return iteratedParam + ".map(__quoteHeader).join(', ')";
             case QUERY:
             case QUERY_PARAMS:
                 return iteratedParam;
@@ -2466,16 +2468,29 @@ private HttpBinding readPayload(
             // If payload is a Union, then we need to parse the string into JavaScript object.
             importUnionDeserializer(writer);
             writer.write("const data: Record<string, any> | undefined "
-                    + "= __expectUnion(await parseBody(output.body, context));");
+                    + "= await parseBody(output.body, context);");
         } else if (target instanceof StringShape || target instanceof DocumentShape) {
             // If payload is String or Document, we need to collect body and convert binary to string.
             writer.write("const data: any = await collectBodyString(output.body, context);");
         } else {
             throw new CodegenException(String.format("Unexpected shape type bound to payload: `%s`",
                     target.getType()));
         }
-        writer.write("contents.$L = $L;", binding.getMemberName(), getOutputValue(context,
+
+        if (target instanceof UnionShape) {
+            writer.openBlock(
+                "if (Object.keys(data ?? {}).length) {",
+                "}",
+                () -> {
+                    writer.write("contents.$L = __expectUnion($L);", binding.getMemberName(), getOutputValue(context,
+                        Location.PAYLOAD, "data", binding.getMember(), target));
+                }
+            );
+        } else {
+            writer.write("contents.$L = $L;", binding.getMemberName(), getOutputValue(context,
                 Location.PAYLOAD, "data", binding.getMember(), target));
+        }
+
         return binding;
     }