no-throw on invoking operationContextParams getter

Author: kuhe

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

@@ -344,7 +344,7 @@ private void generateEndpointParameterInstructionProvider() {
             operationContextParamValues.forEach((name, jmesPathForInputInJs) -> {
                 writer.write(
                     """
-                    $L: { type: \"operationContextParams\", get: (input: any) => $L },
+                    $L: { type: \"operationContextParams\", get: (input?: any) => $L },
                     """,
                     name, jmesPathForInputInJs);
             });

smithy-typescript-codegen/src/main/java/software/amazon/smithy/typescript/codegen/endpointsV2/RuleSetParameterFinder.java

@@ -274,7 +274,7 @@ public Map<String, String> getOperationContextParamValues(OperationShape operati
         Optional<OperationContextParamsTrait> trait = operation.getTrait(OperationContextParamsTrait.class);
         if (trait.isPresent()) {
             trait.get().getParameters().forEach((name, definition) -> {
-                String separator = ".";
+                String separator = "?.";
                 String value = "input";
                 String path = definition.getPath();
 
@@ -289,13 +289,13 @@ public Map<String, String> getOperationContextParamValues(OperationShape operati
                     if (part.startsWith("keys(")) {
                         // Get provided object for which keys are to be extracted.
                         String object = part.substring(5, part.length() - 1);
-                        value = "Object.keys(" + value + separator + object + ")";
+                        value = "Object.keys(" + value + separator + object + " ?? {})";
                         continue;
                     }
 
                     // Process list wildcard expression https://jmespath.org/specification.html#wildcard-expressions
                     if (part.equals("*") || part.equals("[*]")) {
-                        value = "Object.values(" + value + ")";
+                        value = "Object.values(" + value + " ?? {})";
                         continue;
                     }
 

smithy-typescript-codegen/src/test/java/software/amazon/smithy/typescript/codegen/CommandGeneratorTest.java

@@ -39,12 +39,12 @@ public void writesOperationContextParamValues() {
         testCommmandCodegen(
             "endpointsV2/endpoints-operation-context-params.smithy",
             new String[] {
-                "opContextParamIdentifier: { type: \"operationContextParams\", get: (input: any) => input.fooString }",
-                "opContextParamSubExpression: { type: \"operationContextParams\", get: (input: any) => input.fooObj.bar }",
-                "opContextParamWildcardExpressionList: { type: \"operationContextParams\", get: (input: any) => input.fooList }",
-                "opContextParamWildcardExpressionListObj: { type: \"operationContextParams\", get: (input: any) => input.fooListObj.map((obj: any) => obj.key) }",
-                "opContextParamWildcardExpressionHash: { type: \"operationContextParams\", get: (input: any) => Object.values(input.fooObjObj).map((obj: any) => obj.bar) }",
-                "opContextParamKeys: { type: \"operationContextParams\", get: (input: any) => Object.keys(input.fooKeys) }",
+                "opContextParamIdentifier: { type: \"operationContextParams\", get: (input?: any) => input?.fooString }",
+                "opContextParamSubExpression: { type: \"operationContextParams\", get: (input?: any) => input?.fooObj?.bar }",
+                "opContextParamWildcardExpressionList: { type: \"operationContextParams\", get: (input?: any) => input?.fooList }",
+                "opContextParamWildcardExpressionListObj: { type: \"operationContextParams\", get: (input?: any) => input?.fooListObj?.map((obj: any) => obj?.key) }",
+                "opContextParamWildcardExpressionHash: { type: \"operationContextParams\", get: (input?: any) => Object.values(input?.fooObjObj ?? {}).map((obj: any) => obj?.bar) }",
+                "opContextParamKeys: { type: \"operationContextParams\", get: (input?: any) => Object.keys(input?.fooKeys ?? {}) }",
             }
         );
     }