Add handleAPIError helper

- New and improved from ent-search - this one automatically sets flash messages for you so you don't have to pass in a callback!

x-pack/plugins/enterprise_search/public/applications/shared/flash_messages/handle_api_errors.test.ts

@@ -0,0 +1,50 @@
+/*
+ * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+ * or more contributor license agreements. Licensed under the Elastic License;
+ * you may not use this file except in compliance with the Elastic License.
+ */
+
+jest.mock('./', () => ({
+  FlashMessagesLogic: { actions: { setFlashMessages: jest.fn() } },
+}));
+import { FlashMessagesLogic } from './';
+
+import { handleAPIError } from './handle_api_errors';
+
+describe('handleAPIError', () => {
+  const mockHttpError = {
+    body: {
+      statusCode: 404,
+      error: 'Not Found',
+      message: 'Could not find X,Could not find Y,Something else bad happened',
+      attributes: {
+        errors: ['Could not find X', 'Could not find Y', 'Something else bad happened'],
+      },
+    },
+  } as any;
+
+  beforeEach(() => {
+    jest.clearAllMocks();
+  });
+
+  it('converts API errors into flash messages', () => {
+    handleAPIError(mockHttpError);
+
+    expect(FlashMessagesLogic.actions.setFlashMessages).toHaveBeenCalledWith([
+      { type: 'error', message: 'Could not find X' },
+      { type: 'error', message: 'Could not find Y' },
+      { type: 'error', message: 'Something else bad happened' },
+    ]);
+  });
+
+  it('displays a generic error message and re-throws non-API errors', () => {
+    try {
+      handleAPIError(Error('whatever') as any);
+    } catch (e) {
+      expect(e.message).toEqual('whatever');
+      expect(FlashMessagesLogic.actions.setFlashMessages).toHaveBeenCalledWith([
+        { type: 'error', message: 'An unexpected error occurred' },
+      ]);
+    }
+  });
+});

x-pack/plugins/enterprise_search/public/applications/shared/flash_messages/handle_api_errors.ts

@@ -0,0 +1,46 @@
+/*
+ * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+ * or more contributor license agreements. Licensed under the Elastic License;
+ * you may not use this file except in compliance with the Elastic License.
+ */
+
+import { HttpResponse } from 'src/core/public';
+
+import { FlashMessagesLogic, IFlashMessage } from './';
+
+/**
+ * The API errors we are handling can come from one of two ways:
+ *  - When our http calls recieve a response containing an error code, such as a 404 or 500
+ *  - Our own JS while handling a successful response
+ *
+ * In the first case, if it is a purposeful error (like a 404) we will receive an
+ * `errors` property in the response's data, which will contain messages we can
+ * display to the user.
+ */
+interface IErrorResponse {
+  statusCode: number;
+  error: string;
+  message: string;
+  attributes: {
+    errors: string[];
+  };
+}
+
+/**
+ * Converts API/HTTP errors into user-facing Flash Messages
+ */
+export const handleAPIError = (error: HttpResponse<IErrorResponse>) => {
+  const defaultErrorMessage = 'An unexpected error occurred';
+
+  const errorFlashMessages: IFlashMessage[] = Array.isArray(error?.body?.attributes?.errors)
+    ? error.body!.attributes.errors.map((message) => ({ type: 'error', message }))
+    : [{ type: 'error', message: defaultErrorMessage }];
+
+  FlashMessagesLogic.actions.setFlashMessages(errorFlashMessages);
+
+  // If this was a programming error or a failed request (such as a CORS) error,
+  // we rethrow the error so it shows up in the developer console
+  if (!error?.body?.message) {
+    throw error;
+  }
+};