Implement SDK error handling

raiden-ts/src/utils/error.ts

@@ -0,0 +1,26 @@
+export type ErrorDetail = { [key: string]: string };
+
+export default abstract class RaidenError extends Error {
+  code: string;
+  details?: ErrorDetail[];
+
+  constructor(message: string, detail?: ErrorDetail[] | ErrorDetail) {
+    super(message || 'General Error');
+    this.name = 'RaidenError';
+    this.code = this.getCode(message);
+
+    if (detail) {
+      this.details = Array.isArray(detail) ? detail : [detail];
+    }
+  }
+
+  addDetail(detail: ErrorDetail) {
+    if (this.details) {
+      this.details.push(detail);
+    } else {
+      this.details = [detail];
+    }
+  }
+
+  abstract getCode(message: string): string;
+}

raiden-ts/tests/unit/error.spec.ts

@@ -0,0 +1,78 @@
+import { isError } from 'util';
+
+import RaidenError, { ErrorDetail } from '../../src/utils/error';
+
+enum MyCustomErrorCodes {
+  TEST = 'Developer-friendly description',
+}
+
+class MyCustomError extends RaidenError {
+  constructor(message: MyCustomErrorCodes, detail?: ErrorDetail) {
+    super(message, detail);
+    this.name = 'MyCustomError';
+  }
+
+  getCode(message: string): string {
+    return (
+      Object.keys(MyCustomErrorCodes).find(code => Object(MyCustomErrorCodes)[code] === message) ??
+      'GENERAL_ERROR'
+    );
+  }
+}
+
+describe('Test custom error', () => {
+  test('MyCustomError is instance of its custom class', () => {
+    try {
+      throw new MyCustomError(MyCustomErrorCodes.TEST);
+    } catch (err) {
+      expect(err).toBeInstanceOf(MyCustomError);
+      expect(err.name).toEqual('MyCustomError');
+    }
+  });
+
+  test('MyCustomError is an instance of Error', () => {
+    try {
+      throw new MyCustomError(MyCustomErrorCodes.TEST);
+    } catch (err) {
+      expect(err instanceof Error).toBeTruthy();
+      expect(isError(err)).toBeTruthy();
+    }
+  });
+
+  test('Has stack trace w/ class name and developer-friendly message', () => {
+    try {
+      function doSomething() {
+        throw new MyCustomError(MyCustomErrorCodes.TEST);
+      }
+      doSomething();
+    } catch (err) {
+      // Stack trace exists
+      expect(err.stack).toBeDefined();
+
+      // Stack trace starts with the error message
+      expect(err.stack.split('\n').shift()).toEqual(
+        'MyCustomError: Developer-friendly description',
+      );
+
+      // Stack trace contains function where error was thrown
+      expect(err.stack.split('\n')[1]).toContain('doSomething');
+    }
+  });
+
+  test('End user "code" property is set', () => {
+    try {
+      throw new MyCustomError(MyCustomErrorCodes.TEST);
+    } catch (err) {
+      expect(err.code).toBeDefined();
+      expect(err.code).toEqual('TEST');
+    }
+  });
+
+  test('Details can be added and are shown in stack trace', () => {
+    try {
+      throw new MyCustomError(MyCustomErrorCodes.TEST, { foo: 'bar' });
+    } catch (err) {
+      expect(err.details).toEqual([{ foo: 'bar' }]);
+    }
+  });
+});