React Di
Table of contents
Overview
Dependency injection for react based upon inversify.
Install
npm install @hooked74/react-di
Your tsconfig.json needs to be configured with the following flags:
"experimentalDecorators": true,
"emitDecoratorMetadata": true
Usage
Getting started
1. Define injectables (values/class)
Service
import {Injectable, Inject} from '@hooked74/react-di';
@Injectable
export class UserService {
constructor(@Inject private httpClient: SomeHttpClient) {}
getUser() {}
}Config
const CONFIG_TOKEN = 'config'; // or Symbol('config');
const config: Config = {...};2. Inject service/value into react component
import {Inject} from '@hooked74/react-di';
class UserContainer extends Component<any, any> {
@Inject userService: UserService;
@Inject(CONFIG_TOKEN) config: Config;
async componentDidMount() {
const user = await this.userService.getUser();
this.setState({user});
}
render() {
return (<User user={this.state.user} />);
}
}3. Setup module
import {Module} from '@hooked74/react-di';
@Module({
providers: [
{provide: UserService, useClass: UserService},
UserService, // or shorthand
{provide: CONFIG_TOKEN, useValue: config},
{provide: CONFIG_TOKEN, useFactory: context => config}, // or using factory
]
})
class App extends Component {
render() {
return (
<Panel>
<UserContainer/>
</Panel>
);
}
}Injection
Injection from class references
If you want to inject a service instance, simply mark the property with @Inject.
The type from which the instance will be created, will be derived from the
annotated type. Notice, that the type needs to be a class. An interface won't
work, cause it will not exist on runtime anymore (See
Injection via tokens to get it work with interfaces).
@Inject userService: UserService;A services class need to be annotated with @Injectable otherwise it will not
be - of course - injectable.
Injection via tokens
Dependencies can also be identified by a token. This makes sense when injecting a value (for example a configuration) or if you want annotate these properties with interfaces instead of class references.
@Inject(CONFIG_TOKEN) config: Config;Multi injection
Multi injection means that all providers for a specified identifier
will be injected.
So if the annotated type of the dependency is of type Array, the
injection will automatically processed as a multi-injection. In this
case the identifier needs to be passed explicitly:
@Inject(INTERCEPTOR_TOKEN) interceptors: Interceptor[];Inject into React Components
Dependencies of react component need be injected via property injection:
import {Inject} from '@hooked74/react-di';
class UserComponent extends Component<any, any> {
@Inject userService: UserService;
@Inject(OtherService) otherService: OtherService;
@Inject(CONFIG_TOKEN) config: Config;
@Inject(TRANSLATION_TOKEN) translations: Translation[];
...
}Inject into React Functional Components
Dependencies of react component need be injected via useInject hook:
import {useInject} from '@hooked74/react-di';
const UserComponent = () => {
const [otherService, config, translation]: [OtherService, Config, Translation] = useInject(OtherService, CONFIG_TOKEN, TRANSLATION_TOKEN)
...
}Inject into Services
Dependencies of services will be injected via constructor injection:
import {Injectable, Inject} from '@hooked74/react-di';
@Injectable
export class UserService {
constructor(@Inject http: HttpClient,
@Inject(OtherService) otherService: OtherService,
@Inject(HISTORY_TOKEN) history: IHistory) {}
}Sharing providers
Providers can be shared via importing from siblings or inheriting them from parent components.
Importing modules in other modules
Modules can be imported in other modules to share its providers.
@Module({providers: [CommonService]})
class CommonModule extends Component {}
@Module({
imports: [CommonModule],
providers: [UserService],
})
class UserModule extends Component {
@Inject userService: UserService;
@Inject commonService: CommonService;
}
@Module()
class Root extends Component {
render() {
return (
<UserModule/>
);
}Hierarchical shared providers
Nesting Module annotated components in another Module annotated components
is supported.
All defined providers of the parent module will be inherited to its
child modules:
@Module({providers: [UserService]})
class UserModule extends Component {}
@Module({providers: [CommonService]})
class App extends Component {
render() {
return (
<UserModule/> // CommonService will also be available in UserModule
);
}Providers that are already defined in a parent, will be overridden if they are also defined in its child.
Testing
For testing purposes @hooked74/react-di provides a TestUtil component. Nest the
components you want to test in TestUtil and setup its dependencies in
the providers prop of TestUtil:
import {mount} from 'enzyme';
mount(
<TestUtil providers={[{provide: UserService, useClass: UserServiceMock}]}>
<UserProfileContainer/>
</TestUtil>
);or for defining a much simpler mock:
mount(
<TestUtil providers={[{provide: UserService, useValue: {getUser() {...}}}]}>
<UserProfileContainer/>
</TestUtil>
);API
Injectable
Injectable decorator marks a class as available to the inversify Container.
import {Injectable} from '@hooked74/react-di';
@Injectable
export class UserService {}Inject
The Inject/Inject(Identifier) decorator tells the di-system what need to be injected
and in which property the injected value should be referenced.
For functional components an alternative is the useInject(...Identifiers) hook.
Module
All components that should be feedable with the defined providers, need to be nested in a module annotated component - But don't(!) need to be direct children.
@Module({
providers: [...],
imports: [...],
autoBindInjectable: true, // default is false
})
class App extends Component {}
providers (Option)
(optional) Array of all available providers.
Injecting a class constructor
[{provide: UserService, useClass: UserService}]Shorthand
[UserService]All instantiated dependencies will be a singleton by default. If you don't
want a dependency to be singleton set noSingleton to true:
[{provide: UserService, useClass: UserService, noSingleton: true}]Injecting a value
[{provide: UserService, useValue: someUserService}]Injection via factories
Dependencies can be injected via factories. A factory is a simple function, that gets the context of the current scope and returns the value, that will be injected.
[{provide: UserService, useFactory: context => someValue}]
imports (Option)
(optional) Array of all modules that should be imported.
[CommonModule, UserModule]
autoBindInjectable (Option)
(optional, default: false) When autoBindInjectable is set to true, injectable
class constructors don't need to be defined as providers anymore.
They will be available for injection by default.
So that [{provide: UserService, useClass: UserService}] or [UserService]
can be omitted:
@Module({autoBindInjectable: true})
class App extends Component{}<TestUtil autoBindInjectable={true}>
... // UserService will be available anyway
</TestUtil>TestUtil (React Component)
<TestUtil providers={[...]} autoBindInjectable={true}>
...
</TestUtil>Provider (React Component)
The <Provider> component is a react component, that provides low-level
support for inversifyJS containers. In other words: It takes an
inversify container as property. So if you want to use all features
of inversify, this is the component you will fall in love with:
const container = new Container();
container.bind(Ninja).to(Samurai);
<Provider container={container}>
...
</Provider>Development
You can run some built-in commands:
npm run build
Builds the app for production. Your app is ready to be deployed.
npm run analyze
Visualize and analyze your bundle to see which modules are taking up space.
npm run test:watch
Runs the test watcher in an interactive mode. By default, runs tests related to files changed since the last commit.