refactor(example-log-extension): automatically load LogComponent from Mixin

- automatically mount LogComponent
- rename LogLevelMixin to LogMixin
- add new test and refactor existing tests

Author: virkt25

packages/example-log-extension/src/component.ts

@@ -3,9 +3,10 @@
 // This file is licensed under the MIT License.
 // License text available at https://opensource.org/licenses/MIT
 
-import {EXAMPLE_LOG_BINDINGS} from './keys';
 import {Component, ProviderMap} from '@loopback/core';
-import {TimerProvider, LogActionProvider} from './';
+import {EXAMPLE_LOG_BINDINGS} from './keys';
+import {LogActionProvider} from './providers/log-action.provider';
+import {TimerProvider} from './providers/timer.provider';
 
 export class LogComponent implements Component {
   providers?: ProviderMap = {

packages/example-log-extension/src/index.ts

@@ -4,7 +4,7 @@
 // License text available at https://opensource.org/licenses/MIT
 
 export * from './decorators/log.decorator';
-export * from './mixins/log-level.mixin';
+export * from './mixins/log.mixin';
 export * from './providers/log-action.provider';
 export * from './providers/timer.provider';
 export * from './component';

packages/example-log-extension/src/mixins/log-level.mixin.ts renamed to packages/example-log-extension/src/mixins/log.mixin.ts

@@ -5,28 +5,28 @@
 
 import {Constructor} from '@loopback/context';
 import {EXAMPLE_LOG_BINDINGS} from '../keys';
+import {LogComponent} from '../component';
 
 /**
  * A mixin class for Application that can bind logLevel from `options`.
  * Also provides .logLevel() to bind application wide logLevel.
  * Functions with a log level set to logLevel or higher sill log data
  *
  * ```ts
- * class MyApplication extends LogLevelMixin(Application) {}
+ * class MyApplication extends LogMixin(Application) {}
  * ```
  */
 // tslint:disable-next-line:no-any
-export function LogLevelMixin<T extends Constructor<any>>(superClass: T) {
+export function LogMixin<T extends Constructor<any>>(superClass: T) {
   return class extends superClass {
     // A mixin class has to take in a type any[] argument!
     // tslint:disable-next-line:no-any
     constructor(...args: any[]) {
       super(...args);
-      if (!this.options) this.options = {};
-
-      if (this.options.logLevel) {
+      if (this.options && this.options.logLevel) {
         this.logLevel(this.options.logLevel);
       }
+      this.component(LogComponent);
     }
 
     /**

packages/example-log-extension/test/acceptance/log.extension.acceptance.ts

@@ -18,8 +18,7 @@ import {
 } from '@loopback/rest';
 import {get, param} from '@loopback/openapi-v3';
 import {
-  LogComponent,
-  LogLevelMixin,
+  LogMixin,
   LOG_LEVEL,
   log,
   EXAMPLE_LOG_BINDINGS,
@@ -46,7 +45,7 @@ describe('log extension acceptance test', () => {
   let server: RestServer;
   let spy: SinonSpy;
 
-  class LogApp extends LogLevelMixin(RestApplication) {}
+  class LogApp extends LogMixin(RestApplication) {}
 
   const debugMatch: string = chalk.white(
     'DEBUG: /debug :: MyController.debug() => debug called',
@@ -240,8 +239,6 @@ describe('log extension acceptance test', () => {
 
   async function createApp() {
     app = new LogApp();
-    app.component(LogComponent);
-
     app.bind(EXAMPLE_LOG_BINDINGS.TIMER).to(timer);
     app.bind(EXAMPLE_LOG_BINDINGS.LOGGER).to(logToMemory);
     server = await app.getServer(RestServer);

packages/example-log-extension/test/unit/mixins/log-level.mixin.unit.ts renamed to packages/example-log-extension/test/unit/mixins/log.mixin.unit.ts

@@ -5,32 +5,42 @@
 
 import {expect} from '@loopback/testlab';
 import {Application} from '@loopback/core';
-import {LogLevelMixin, LOG_LEVEL, EXAMPLE_LOG_BINDINGS} from '../../..';
+import {LogMixin, LOG_LEVEL, EXAMPLE_LOG_BINDINGS} from '../../..';
+
+describe('LogMixin (unit)', () => {
+  let myApp: AppWithLogMixin;
+
+  beforeEach(getApp);
 
-describe('LogLevelMixin (unit)', () => {
   it('mixed class has .logLevel()', () => {
-    const myApp = new AppWithLogLevel();
-    expect(typeof myApp.logLevel).to.be.eql('function');
+    expect(myApp.logLevel).to.be.a.Function();
   });
 
   it('binds LogLevel from constructor', () => {
-    const myApp = new AppWithLogLevel({
+    myApp = new AppWithLogMixin({
       logLevel: LOG_LEVEL.ERROR,
     });
-
-    expectLogLevelToBeBound(myApp);
+    expectLogLevelToBeBound();
   });
 
   it('bind logLevel from app.logLevel()', () => {
-    const myApp = new AppWithLogLevel();
     myApp.logLevel(LOG_LEVEL.ERROR);
-    expectLogLevelToBeBound(myApp);
+    expectLogLevelToBeBound();
   });
 
-  class AppWithLogLevel extends LogLevelMixin(Application) {}
+  it('adds LogComponent to target class', () => {
+    const boundComponent = myApp.find('components.*').map(b => b.key);
+    expect(boundComponent).to.containEql('components.LogComponent');
+  });
 
-  function expectLogLevelToBeBound(myApp: Application) {
+  class AppWithLogMixin extends LogMixin(Application) {}
+
+  function expectLogLevelToBeBound() {
     const logLevel = myApp.getSync(EXAMPLE_LOG_BINDINGS.APP_LOG_LEVEL);
     expect(logLevel).to.be.eql(LOG_LEVEL.ERROR);
   }
+
+  function getApp() {
+    myApp = new AppWithLogMixin();
+  }
 });