Fix set serialization via loops (#975)

Author: kstich

codegen/smithy-aws-typescript-codegen/src/main/java/software/amazon/smithy/aws/typescript/codegen/JsonShapeSerVisitor.java

@@ -56,10 +56,11 @@ public void serializeCollection(GenerationContext context, CollectionShape shape
         TypeScriptWriter writer = context.getWriter();
         Shape target = context.getModel().expectShape(shape.getMember().getTarget());
 
-        // Dispatch to the input value provider for any additional handling.
-        writer.openBlock("return (input || []).map(entry =>", ");", () -> {
-            writer.write(target.accept(getMemberVisitor("entry")));
-        });
+        writer.write("const contents = [];");
+        writer.openBlock("for (let entry of input) {", "}", () ->
+                // Dispatch to the input value provider for any additional handling.
+                writer.write("contents.push($L);", target.accept(getMemberVisitor("entry"))));
+        writer.write("return contents;");
     }
 
     @Override

codegen/smithy-aws-typescript-codegen/src/main/java/software/amazon/smithy/aws/typescript/codegen/QueryShapeSerVisitor.java

@@ -64,8 +64,8 @@ protected void serializeCollection(GenerationContext context, CollectionShape sh
         writer.write("const entries: any = {};");
         // Set up a counter to increment the member entries.
         writer.write("let counter = 1;");
-        // Dispatch to the input value provider for any additional handling.
-        writer.openBlock("(input || []).map(entry => {", "});", () -> {
+        writer.openBlock("for (let entry of input) {", "}", () -> {
+            // Dispatch to the input value provider for any additional handling.
             serializeUnnamedMemberEntryList(context, target, "entry", locationName);
             writer.write("counter++;");
         });

codegen/smithy-aws-typescript-codegen/src/main/java/software/amazon/smithy/aws/typescript/codegen/XmlShapeSerVisitor.java

@@ -70,8 +70,8 @@ protected void serializeCollection(GenerationContext context, CollectionShape sh
 
         // Set up a location to store all of the child node(s).
         writer.write("const collectedNodes: any = [];");
-        // Dispatch to the input value provider for any additional handling.
-        writer.openBlock("(input || []).map(entry => {", "});", () -> {
+        writer.openBlock("for (let entry of input) {", "}", () -> {
+            // Dispatch to the input value provider for any additional handling.
             writer.write("const node = $L;", target.accept(getMemberVisitor("entry")));
             writer.write("collectedNodes.push(node.withName($S));", locationName);
         });