fix: Use for … of loop instead of for … in (#1209)

Author: mjameswh

packages/common/src/converter/payload-converter.ts

@@ -268,8 +268,7 @@ export class SearchAttributePayloadConverter implements PayloadConverter {
       const firstValue = values[0];
       const firstType = typeof firstValue;
       if (firstType === 'object') {
-        for (const idx in values) {
-          const value = values[idx];
+        for (const [idx, value] of values.entries()) {
           if (!(value instanceof Date)) {
             throw new ValueError(
               `SearchAttribute values must arrays of strings, numbers, booleans, or Dates. The value ${value} at index ${idx} is of type ${typeof value}`
@@ -281,8 +280,7 @@ export class SearchAttributePayloadConverter implements PayloadConverter {
           throw new ValueError(`SearchAttribute array values must be: string | number | boolean | Date`);
         }
 
-        for (const idx in values) {
-          const value = values[idx];
+        for (const [idx, value] of values.entries()) {
           if (typeof value !== firstType) {
             throw new ValueError(
               `All SearchAttribute array values must be of the same type. The first value ${firstValue} of type ${firstType} doesn't match value ${value} of type ${typeof value} at index ${idx}`

packages/test/src/test-payload-converter.ts

@@ -10,6 +10,7 @@ import {
   METADATA_ENCODING_KEY,
   METADATA_MESSAGE_TYPE_KEY,
   PayloadConverterError,
+  SearchAttributePayloadConverter,
   UndefinedPayloadConverter,
   ValueError,
 } from '@temporalio/common';
@@ -171,6 +172,21 @@ test('ProtobufJSONPayloadConverter converts binary', (t) => {
   t.deepEqual(testInstance.data, instance.data);
 });
 
+test(`SearchAttributePayloadConverter doesn't fail if Array.prototype contains enumerable properties`, (t) => {
+  try {
+    const converter = new SearchAttributePayloadConverter();
+    Object.defineProperty(Array.prototype, 'foo', {
+      configurable: true,
+      value: 123,
+      enumerable: true,
+    });
+    converter.toPayload(['test']);
+    t.pass();
+  } finally {
+    delete (Array.prototype as any).foo;
+  }
+});
+
 if (RUN_INTEGRATION_TESTS) {
   test('Worker throws decoding proto JSON without WorkerOptions.dataConverter', async (t) => {
     let markErrorThrown: () => void;