address feedbacks: fix indentation; readResponseBody; add docs

Author: AllanZhengYP

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

@@ -720,6 +720,7 @@ private List<HttpBinding> readResponseBody(
                 .orElse(false);
 
         if (!documentBindings.isEmpty()) {
+            // If response has document binding, the body can be parsed to JavaScript object.
             writer.write("const data: any = await parseBody(output.body, context);");
             deserializeOutputDocument(context, operationOrError, documentBindings);
             return documentBindings;
@@ -734,12 +735,11 @@ private List<HttpBinding> readResponseBody(
             } else if (target instanceof BlobShape) {
                 // If payload is blob, only need to collect stream to binary data(Uint8Array).
                 writer.write("const data: any = await collectBody(output.body, context);");
-            } else if (target instanceof CollectionShape || target instanceof StructureShape) {
-                // If body is Collection or Structure, they we need to parse the string into JavaScript object.
+            } else if (target instanceof StructureShape || target instanceof UnionShape) {
+                // If body is Structure or Union, they we need to parse the string into JavaScript object.
                 writer.write("const data: any = await parseBody(output.body, context);");
             } else {
-                // If payload is other scalar types(not Collection or Structure), because payload will be values in
-                // string instead of valid JSON or XML. So we need to collect body and encode binary to string.
+                // If payload is string, we need to collect body and encode binary to string.
                 writer.write("const data: any = await collectBodyString(output.body, context);");
             }
             writer.write("contents.$L = $L;", binding.getMemberName(), getOutputValue(context,

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

@@ -112,6 +112,7 @@ static void generateCollectBody(GenerationContext context) {
         TypeScriptWriter writer = context.getWriter();
 
         writer.addImport("SerdeContext", "__SerdeContext", "@aws-sdk/types");
+        writer.write("// Collect low-level response body stream to Uint8Array.");
         writer.openBlock("const collectBody = (streamBody: any, context: __SerdeContext): Promise<Uint8Array> => {",
                 "};", () -> {
             writer.write("return context.streamCollector(streamBody) || new Uint8Array();");
@@ -124,6 +125,7 @@ static void generateCollectBodyString(GenerationContext context) {
         TypeScriptWriter writer = context.getWriter();
 
         writer.addImport("SerdeContext", "__SerdeContext", "@aws-sdk/types");
+        writer.write("// Encode Uint8Array data into string with utf-8.");
         writer.openBlock("const collectBodyString = (streamBody: any, context: __SerdeContext): Promise<string> => {",
                 "};", () -> {
             writer.write("return collectBody(streamBody, context).then(body => context.utf8Encoder(body));");
@@ -167,11 +169,12 @@ static Set<StructureShape> generateErrorDispatcher(
             // Prepare error response for parsing error code. If error code needs to be parsed from response body
             // then we collect body and parse it to JS object, otherwise leave the response body as is.
             writer.openBlock(
-                    "const $L: any = {", "};", shouldParseErrorBody ? "parsedOutput" : "errorOutput", () -> {
-                writer.write("...output,");
-                writer.write("body: $L,",
-                        shouldParseErrorBody ? "await parseBody(output.body, context)" : "output.body");
-            });
+                    "const $L: any = {", "};", shouldParseErrorBody ? "parsedOutput" : "errorOutput",
+                    () -> {
+                        writer.write("...output,");
+                        writer.write("body: $L,",
+                                shouldParseErrorBody ? "await parseBody(output.body, context)" : "output.body");
+                    });
 
             // Error responses must be at least SmithyException and MetadataBearer implementations.
             writer.addImport("SmithyException", "__SmithyException",