fix: fix restify instrumentation utils that might accept undefined ty…

…pes (#690)

plugins/node/opentelemetry-instrumentation-restify/src/utils.ts

@@ -15,24 +15,20 @@
  */
 
 // util.types.isPromise is supported from 10.0.0
-export const isPromise = (value: any): value is Promise<unknown> => {
-  if (
+export const isPromise = (value?: any): value is Promise<unknown> => {
+  return !!(
+    value &&
     typeof value.then === 'function' &&
     typeof value.catch === 'function' &&
     value.toString() === '[object Promise]'
-  ) {
-    return true;
-  }
-  return false;
+  );
 };
 
 // util.types.isAsyncFunction is supported from 10.0.0
-export const isAsyncFunction = (value: unknown) => {
-  if (
+export const isAsyncFunction = (value?: unknown) => {
+  return !!(
+    value &&
     typeof value === 'function' &&
     value.constructor?.name === 'AsyncFunction'
-  ) {
-    return true;
-  }
-  return false;
+  );
 };

plugins/node/opentelemetry-instrumentation-restify/test/utils.test.ts

@@ -0,0 +1,60 @@
+/*
+ * Copyright The OpenTelemetry Authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+import { isAsyncFunction, isPromise } from '../src/utils';
+import * as assert from 'assert';
+
+describe('utils', () => {
+  describe('isPromise', () => {
+    it('should be able to validate a promise to be true', () => {
+      assert.strictEqual(isPromise(Promise.resolve()), true);
+    });
+
+    it('should be able to validate non-promise to be false', () => {
+      assert.strictEqual(isPromise(), false);
+      assert.strictEqual(isPromise(null), false);
+      assert.strictEqual(isPromise({}), false);
+      assert.strictEqual(isPromise('string'), false);
+      assert.strictEqual(isPromise(123), false);
+      assert.strictEqual(
+        isPromise(() => {}),
+        false
+      );
+      assert.strictEqual(isPromise((async () => {}) as any), false);
+    });
+  });
+
+  describe('isAsyncFunction', () => {
+    it('should be able to validate an async function to be true', () => {
+      assert.strictEqual(
+        isAsyncFunction(async () => {}),
+        true
+      );
+    });
+
+    it('should be able to validate non async function to be false', () => {
+      assert.strictEqual(isAsyncFunction(), false);
+      assert.strictEqual(isAsyncFunction(null), false);
+      assert.strictEqual(isAsyncFunction({}), false);
+      assert.strictEqual(isAsyncFunction('string'), false);
+      assert.strictEqual(isAsyncFunction(123), false);
+      assert.strictEqual(
+        isAsyncFunction(() => {}),
+        false
+      );
+      assert.strictEqual(isAsyncFunction(Promise.resolve()), false);
+    });
+  });
+});