NodeJS Spring style Inversifyjs
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This document discusses dependency injection (DI) and inversion of control (IOC) design patterns. It explains that DI allows defining dependencies externally rather than hardcoding them, improving testability. IOC builds on DI by having a lightweight container manage object construction and dependency graph. The document uses JavaScript examples to demonstrate an InversifyJS library that implements IOC for JavaScript applications in a similar way that Spring Framework does for Java apps.
![INVERSIFYJSINVERSIFYJS
Why TypeScript ?
How a container know who depends of who ?
class A {
constructor (b) {
this.b = b;
}
}
'b' is just a parameter name. So, how to know to build it ?
someModule.controller('MyController', ['$scope', 'dep1', function($scope, dep1) {
...
$scope.aMethod = function() {
...
}
}]);
In AngularJS, the names was 'injection keys'](https://image.slidesharecdn.com/nodejs-spring-style-inversifyjs-181009165024/85/NodeJS-Spring-style-Inversifyjs-17-320.jpg)
![import { Dependencies, Controller, RequestMapping, RequestMethod } from 'nest.js';
@Controller({ path: 'users' })
@Dependencies([ UsersService ])
export class UsersController {
constructor(usersService) {
this.usersService = usersService;
}
@Get()
getAllUsers(req, res, next) {
this.usersService.getAllUsers().then(users => res.status(200).json(users));
}
@Get('/:id')
getUser(req, res, next) {
this.usersService.getUser(+req.params.id).then(user => res.status(200).json(user));
}
@Post()
addUser(req, res, next) {
this.usersService.addUser(req.body.user).then(msg => res.status(201).json(msg));
}
}
ONE MORE THINGONE MORE THING
Spring & Spring MVC in Node.JS !](https://image.slidesharecdn.com/nodejs-spring-style-inversifyjs-181009165024/85/NodeJS-Spring-style-Inversifyjs-20-320.jpg)
NodeJS Spring style Inversifyjs
- 2. FAIT MOI RÊVERFAIT MOI RÊVER DI, Ioc, Kamouloxx ? Inversify Demo
- 3. DEPENDENCY INJECTIONDEPENDENCY INJECTION AKA : DIAKA : DI
- 4. DI : WHY ?DI : WHY ? Lets imagine two classes A and B. A is using B : A B class A { constructor (){ this.b = new B(SECRET_KEY); } } No Factorisation Untestable Strongly coupled Bad separation of concerns
- 5. DI : WHAT ?DI : WHAT ? The fifth of principles in OOP. Dependencies should be given. SOLID class A { constructor (private b:B){ } } A BC import A from './A'; import B from './B'; const b = new B(); const a = new A(b); // ... const anotherService = new D(b);
- 6. DI : WHAT ?DI : WHAT ? Easy to test : describe('Class A', () => { it('should behaves as expected', ()=> { // given const mockOfB = { fakeMethod() { /* do something */ } }; const a = new A (mockOfB); // when -> then ... }); });
- 7. INJECTION OF CONTROLINJECTION OF CONTROL AKA : IOCAKA : IOC
- 8. IOC : WHY ?IOC : WHY ? DI, is good, but give the dependencies at all is boring ! import UserService from '../service/user-service'; import SlackService from '../service/slack/slack-service'; import TenKiloService from '../service/ten-kilo/ten-kilo'; import axios from 'axios'; import bluebird from 'bluebird'; const userService = new UserService( new SlackService(axios), new TenKiloService(axios), bluebird );
- 9. IOC : WHAT ?IOC : WHAT ? IOC is a design pattern, used to dissociate elements in OOP and give an elegant way to build these elements. A BC Lightweight container
- 10. IOC : WHAT ?IOC : WHAT ? IOC is a design pattern, used to dissociate elements in OOP and give an elegant way to build these elements. A BC Lightweight container
- 11. IOC : WHAT ?IOC : WHAT ? IOC is a design pattern, used to dissociate elements in OOP and give an elegant way to build these elements. A BC Lightweight containerResponsible of elements building & connect them
- 12. IOC : SPRING, THE IOC FRAMEWORK FOR JAVAIOC : SPRING, THE IOC FRAMEWORK FOR JAVA @Controller class VetController { private final VetRepository vets; @Autowired public VetController(VetRepository clinicService) { this.vets = clinicService; } @RequestMapping(value = { "/vets.html" }) public String showVetList(Map<String, Object> model) { Vets vets = new Vets(); vets.getVetList().addAll(this.vets.findAll()); model.put("vets", vets); return "vets/vetList"; } @RequestMapping(value = { "/vets.json", "/vets.xml" }) public @ResponseBody Vets showResourcesVetList() { Vets vets = new Vets(); vets.getVetList().addAll(this.vets.findAll()); return vets; } }
- 13. SO, IOC IN JAVASCRIPT ?SO, IOC IN JAVASCRIPT ?
- 15. INVERSIFYJSINVERSIFYJS A powerful and lightweight inversion of control container for JavaScript & Node.js apps powered by TypeScript.
- 16. INVERSIFYJSINVERSIFYJS A powerful and lightweight inversion of control container for JavaScript & Node.js apps powered by TypeScript. Powered by TypeScript ???
- 17. INVERSIFYJSINVERSIFYJS Why TypeScript ? How a container know who depends of who ? class A { constructor (b) { this.b = b; } } 'b' is just a parameter name. So, how to know to build it ? someModule.controller('MyController', ['$scope', 'dep1', function($scope, dep1) { ... $scope.aMethod = function() { ... } }]); In AngularJS, the names was 'injection keys'
- 19. CONCLUSIONCONCLUSION It's cool, but is it really useful in JavaScript ? Mock a dependency is easy in NodeJS DI why not, but IOC it's maybe too much
- 20. import { Dependencies, Controller, RequestMapping, RequestMethod } from 'nest.js'; @Controller({ path: 'users' }) @Dependencies([ UsersService ]) export class UsersController { constructor(usersService) { this.usersService = usersService; } @Get() getAllUsers(req, res, next) { this.usersService.getAllUsers().then(users => res.status(200).json(users)); } @Get('/:id') getUser(req, res, next) { this.usersService.getUser(+req.params.id).then(user => res.status(200).json(user)); } @Post() addUser(req, res, next) { this.usersService.addUser(req.body.user).then(msg => res.status(201).json(msg)); } } ONE MORE THINGONE MORE THING Spring & Spring MVC in Node.JS !