feat(init): add standard errors and methods

jest.unit.env.ts

@@ -1,8 +1,9 @@
-import { stage, Stage } from './src/utils/environment';
-
 /**
  * sanity check that unit tests are only run in 'test' environment
  * - if they are run in prod environment, we could load a bunch of junk data into our prod databases, which would be no bueno
  */
-if (stage !== Stage.TEST && process.env.I_KNOW_WHAT_IM_DOING !== 'true')
+if (
+  (process.env.NODE_ENV !== 'test' || process.env.STAGE) &&
+  process.env.I_KNOW_WHAT_IM_DOING !== 'true'
+)
   throw new Error(`unit-test is not targeting stage 'test'`);

package.json

@@ -80,5 +80,8 @@
     "commitizen": {
       "path": "./node_modules/cz-conventional-changelog"
     }
+  },
+  "dependencies": {
+    "type-fns": "0.9.0"
   }
 }

src/BadRequestError.test.ts

@@ -0,0 +1,10 @@
+import { BadRequestError } from './BadRequestError';
+
+describe('BadRequestError', () => {
+  it('should produce a helpful, observable error message', () => {
+    const error = new BadRequestError('no tires on the vehicle', {
+      tires: [],
+    });
+    expect(error).toMatchSnapshot();
+  });
+});

src/BadRequestError.ts

@@ -0,0 +1,17 @@
+import { HelpfulError } from './HelpfulError';
+
+/**
+ * BadRequestError errors are used to explicitly declare that your logic has successfully rejected a request
+ *
+ * Named after HTTPStatusCode_400
+ * - > The server cannot or will not process the request due to an apparent caller error
+ * - https://developer.mozilla.org/en-US/docs/Web/HTTP/Status/400
+ *
+ * Commonly used to return an error to the caller while marking the execution as successful
+ * - e.g., the [simple-lambda-handlers](https://github.com/ehmpathy/simple-lambda-handlers) library returns an error to the caller (to notify them of the rejection) while marking the lambda invocation as successful (to avoid cloudwatch metric errors and automated retries)
+ */
+export class BadRequestError extends HelpfulError {
+  constructor(message: string, metadata?: Record<string, any>) {
+    super(['BadRequestError: ', message].join(''), metadata);
+  }
+}

src/HelpfulError.test.ts

@@ -0,0 +1,10 @@
+import { HelpfulError } from './HelpfulError';
+
+describe('HelpfulError', () => {
+  it('should produce a helpful, observable error message', () => {
+    const error = new HelpfulError('the dogs were let out', {
+      who: 'your mom',
+    });
+    expect(error).toMatchSnapshot();
+  });
+});