Introduce FE lib/logger for errors

- This way we can encapsulate our calls to console.error
- We can also do some smart Sentry stuff through this
  function in the future

app/assets/javascripts/deploy_freeze/store/actions.js

 import Api from '~/api';
 import createFlash from '~/flash';
+import { logError } from '~/lib/logger';
 import { __ } from '~/locale';
 import * as types from './mutation_types';
 
@@ -63,8 +64,7 @@ export const deleteFreezePeriod = ({ state, commit }, { id }) => {
       });
       commit(types.RECEIVE_DELETE_FREEZE_PERIOD_ERROR, id);
 
-      // eslint-disable-next-line no-console
-      console.error('[gitlab] Unable to delete deploy freeze:', e);
+      logError(`Unable to delete deploy freeze`, e);
     });
 };
 

app/assets/javascripts/lib/logger/index.js

+/* eslint-disable no-console */
+export const LOG_PREFIX = '[gitlab]';
+
+export const logError = (message = '', ...args) => {
+  console.error(LOG_PREFIX, `${message}\n`, ...args);
+};

spec/frontend/deploy_freeze/store/actions_spec.js

@@ -5,6 +5,7 @@ import * as actions from '~/deploy_freeze/store/actions';
 import * as types from '~/deploy_freeze/store/mutation_types';
 import getInitialState from '~/deploy_freeze/store/state';
 import createFlash from '~/flash';
+import * as logger from '~/lib/logger';
 import axios from '~/lib/utils/axios_utils';
 import { freezePeriodsFixture, timezoneDataFixture } from '../helpers';
 
@@ -218,7 +219,7 @@ describe('deploy freeze store actions', () => {
     });
 
     it('should show flash error and set error in state on delete failure', () => {
-      const errorSpy = jest.spyOn(console, 'error').mockImplementation();
+      jest.spyOn(logger, 'logError').mockImplementation();
       const error = new Error();
       Api.deleteFreezePeriod.mockRejectedValue(error);
 
@@ -234,7 +235,7 @@ describe('deploy freeze store actions', () => {
         () => {
           expect(createFlash).toHaveBeenCalled();
 
-          expect(errorSpy).toHaveBeenCalledWith('[gitlab] Unable to delete deploy freeze:', error);
+          expect(logger.logError).toHaveBeenCalledWith('Unable to delete deploy freeze', error);
         },
       );
     });

spec/frontend/lib/logger/index_spec.js

+import { logError, LOG_PREFIX } from '~/lib/logger';
+
+describe('~/lib/logger', () => {
+  let consoleErrorSpy;
+
+  beforeEach(() => {
+    consoleErrorSpy = jest.spyOn(console, 'error');
+    consoleErrorSpy.mockImplementation();
+  });
+
+  describe('logError', () => {
+    it('sends given message to console.error', () => {
+      const message = 'Lorem ipsum dolar sit amit';
+      const error = new Error('lorem ipsum');
+
+      expect(consoleErrorSpy).not.toHaveBeenCalled();
+
+      logError(message, error);
+
+      expect(consoleErrorSpy).toHaveBeenCalledWith(LOG_PREFIX, `${message}\n`, error);
+    });
+  });
+});