Add enum utility tests

src/utils/enums.ts

@@ -1,5 +1,5 @@
 /*
-Copyright 2020 The Matrix.org Foundation C.I.C.
+Copyright 2020, 2021 The Matrix.org Foundation C.I.C.
 
 Licensed under the Apache License, Version 2.0 (the "License");
 you may not use this file except in compliance with the License.
@@ -19,11 +19,23 @@ limitations under the License.
  * @param e The enum.
  * @returns The enum values.
  */
-export function getEnumValues<T>(e: any): T[] {
+export function getEnumValues(e: any): (string | number)[] {
+    // String-based enums will simply be objects ({Key: "value"}), but number-based
+    // enums will instead map themselves twice: in one direction for {Key: 12} and
+    // the reverse for easy lookup, presumably ({12: Key}). In the reverse mapping,
+    // the key is a string, not a number.
+    //
+    // For this reason, we try to determine what kind of enum we're dealing with.
+
     const keys = Object.keys(e);
-    return keys
-        .filter(k => ['string', 'number'].includes(typeof(e[k])))
-        .map(k => e[k]);
+    const values: (string | number)[] = [];
+    for (const key of keys) {
+        const value = e[key];
+        if (Number.isFinite(value) || e[value.toString()] !== Number(key)) {
+            values.push(value);
+        }
+    }
+    return values;
 }
 
 /**

test/enums-test.ts

@@ -0,0 +1,67 @@
+/*
+Copyright 2021 The Matrix.org Foundation C.I.C.
+
+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
+
+    http://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 {getEnumValues, isEnumValue} from "../src/utils/enums";
+
+enum TestStringEnum {
+    First = "__first__",
+    Second = "__second__",
+}
+
+enum TestNumberEnum {
+    FirstKey = 10,
+    SecondKey = 20,
+}
+
+describe('enums', () => {
+    describe('getEnumValues', () => {
+        it('should work on string enums', () => {
+            const result = getEnumValues(TestStringEnum);
+            expect(result).toBeDefined();
+            expect(result).toHaveLength(2);
+            expect(result).toEqual(['__first__', '__second__']);
+        });
+
+        it('should work on number enums', () => {
+            const result = getEnumValues(TestNumberEnum);
+            expect(result).toBeDefined();
+            expect(result).toHaveLength(2);
+            expect(result).toEqual([10, 20]);
+        });
+    });
+
+    describe('isEnumValue', () => {
+        it('should return true on values in a string enum', () => {
+            const result = isEnumValue(TestStringEnum, '__first__');
+            expect(result).toBe(true);
+        });
+
+        it('should return false on values not in a string enum', () => {
+            const result = isEnumValue(TestStringEnum, 'not a value');
+            expect(result).toBe(false);
+        });
+
+        it('should return true on values in a number enum', () => {
+            const result = isEnumValue(TestNumberEnum, 10);
+            expect(result).toBe(true);
+        });
+
+        it('should return false on values not in a number enum', () => {
+            const result = isEnumValue(TestStringEnum, 99);
+            expect(result).toBe(false);
+        });
+    });
+});