feat(utils): add serializeError helper

packages/utils/src/index.ts

@@ -46,6 +46,7 @@ export * from './promiseAllSequence';
 export * from './redactUserPath';
 export * from './resolveAfter';
 export * from './scheduleAction';
+export * from './serializeError';
 export * from './splitStringEveryNCharacters';
 export * from './throttler';
 export * from './throwError';

packages/utils/src/serializeError.ts

@@ -0,0 +1,15 @@
+/**
+ * Serialize an error of unknown type to a string.
+ */
+export const serializeError = (error: unknown): string => {
+    // Error instances are objects, but have no JSON printable properties
+    if (error instanceof Error) {
+        return error.toString();
+    }
+    if (typeof error === 'object') {
+        return JSON.stringify(error);
+    }
+
+    // assumed to be a primitive type; exotic types such as function will also be simply stringified
+    return `${error}`;
+};

packages/utils/tests/serializeError.test.ts

@@ -0,0 +1,30 @@
+import { serializeError } from '../src/serializeError';
+
+class CustomError extends Error {
+    somethingExtra = 'extra stuff';
+
+    toString() {
+        return `${super.toString()} + ${this.somethingExtra} `;
+    }
+}
+
+describe(serializeError.name, () => {
+    it('serializes an Error instance', () => {
+        const error = new Error('example message');
+        expect(serializeError(error)).toBe('Error: example message');
+
+        const customError = new CustomError('example message');
+        expect(serializeError(customError)).toBe('Error: example message + extra stuff ');
+    });
+
+    it('serializes a plain object', () => {
+        const error = { message: 'test' };
+        expect(serializeError(error)).toBe(JSON.stringify(error));
+    });
+
+    it('serializes a primitive', () => {
+        expect(serializeError('test')).toBe('test');
+        expect(serializeError(123)).toBe('123');
+        expect(serializeError(false)).toBe('false');
+    });
+});