Components and decorators to connect react with inversify.
npm install inversify-reactnpm install --save inversify-react
yarn add inversify-react
react
inversify
reflect-metadata
`
Keep in mind that Inversify uses decorators, which requires some setup for your build process.
Read more about decorators:
* https://github.com/inversify/InversifyJS#installation
* https://github.com/loganfsmyth/babel-plugin-transform-decorators-legacy
* https://www.typescriptlang.org/docs/handbook/decorators.html
inversify-react also uses decorators, but only when used in Class Components.
Usage overview
Usage is pretty similar to React Context.
1. Wrap React component tree with Provider and Container from inversify-react – just like React Context.Provider
`js
import { Provider } from 'inversify-react';
...
...
`
2. Use dependencies from that container in child components
`ts
import { resolve, useInjection } from 'inversify-react';
...
// In functional component – via hooks
const ChildComponent: React.FC = () => {
const foo = useInjection(Foo);
...
};
// or in class component – via decorated fields
class ChildComponent extends React.Component {
@resolve
private readonly foo: Foo;
...
}
`
Provider
`js
...
`
* provides contextual IoC container for children, similar to React Context.Provider
* can automatically establish hierarchy of containers in React tree when you use multiple Providers (e.g. in a big modular app)
* props:
* container - container instance or container factory function
* standalone - (optional prop, false by default) whether to skip hierarchy of containers. Could be useful if you already control container hierarchy and would like to ignore React-tree-based hierarchy.
`ts
import * as React from 'react';
import { Container } from 'inversify';
import { Provider } from 'inversify-react';
// in functional component
const AppOrModuleRoot: React.FC = () => {
return (
{
const container = new Container();
container.bind(Foo).toSelf();
container.bind(Bar).toSelf();
return container;
}}>
{/...children.../}
);
};
// or class component
class AppOrModuleRoot extends React.Component {
// you can create and store container instance explicitly,
// or use factory function like in functional component example above
private readonly container = new Container();
constructor(props: {}, context: {}) {
super(props, context);
const { container } = this;
container.bind(Foo).toSelf();
container.bind(Bar).toSelf();
}
render() {
return (
{/...children.../}
);
}
}
`
React hooks
$3
`ts
const foo = useInjection(Foo);
`
* very similar to React.useContext hook, resolves dependency by id
$3
`ts
// e.g. Foo and Bar are not bound
const foo = useOptionalInjection(Foo); // will return undefined
// or
const bar = useOptionalInjection(Bar, () => 'defaultBar'); // will return 'defaultBar'
`
* resolves optional dependency
* default value can be defined via lazy resolving function (2nd argument)
`ts
const foo = useOptionalInjection(Foo, () => myDefault);
// foo === myDefault
// ^ Foo | typeof myDefault
`
That function conveniently receives container as argument, so you could instantiate your default using container (e.g. if it has dependencies)
`ts
const foo = useOptionalInjection(Foo, container => container.resolve(X));
`
$3
`ts
const container = useContainer();
// or
const foo = useContainer(container => container.resolve(Foo));
`
* low-level hook, resolves container itself
* has overload with callback to immediately resolve value from container, so could be used for more exotic API, e.g. named or tagged bindings
$3
`ts
const bars = useAllInjections(Bar);
``
* @see multi-inject
For more examples, please refer to tests: test/hooks.tsx
React component decorators (for classes)
$3
`ts
@resolve
foo: Foo;
// or strict and semantic, see tips below
@resolve
private readonly foo!: Foo;
`
* resolves service from container
* requires reflect-metadata and emitDecoratorMetadata
`ts
// or pass service identifier explicitly
// e.g. if you deal with interfaces and/or don't want to use field type (via reflect-metadata)
@resolve(IFooServiceId)
private readonly foo!: IFoo;
`
$3
`ts
@resolve.optional
private readonly foo?: Foo;
`
* tries to resolve service from container, but returns undefined if service cannot be obtained
* requires reflect-metadata and emitDecoratorMetadata
@resolve.optional(serviceId, defaultValue?)
* obtains service from container passed down in the React tree, returns defaultValue if service cannot be obtained
`ts
class ChildComponent extends React.Component {
@resolve
private readonly foo!: Foo;
@resolve(Bar)
private readonly bar!: Bar;
@resolve.optional(Baz)
private readonly opt?: Baz;
...
}
// you can also use dependency in constructor,
// just don't forget to call super with context
// @see https://github.com/facebook/react/issues/13944
constructor(props: {}, context: {}) {
super(props, context);
console.log(this.foo.name);
}
`
$3
`ts
@resolve.all('Foo')
private readonly foo!: Foo[];
`
* tries to resolve all services from container, fails if no services are bound to given service identifier
* requires reflect-metadata and emitDecoratorMetadata, but __cannot be used without explicitly specifying service identifier__
@resolve.all(serviceId)
* obtains services from container passed down in the React tree
`ts
class ChildComponent extends React.Component {
@resolve.all(Baz)
private readonly all!: Baz[];
...
}
`
$3
`ts
@resolve.optional.all('Foo')
private readonly foo!: Foo[];
`
* tries to resolve all services from container, returns empty array if none are registered
* requires reflect-metadata and emitDecoratorMetadata, but __cannot be used without explicitly specifying service identifier__
@resolve.optional.all(serviceId)
* obtains services from container passed down in the React tree
`ts
class ChildComponent extends React.Component {
@resolve.optional.all(Baz)
private readonly allorempty!: Baz[];
...
}
`
Notes, tips
1. \[TypeScript tip\] private readonly for @resolve-ed fields is not required, but technically it's more accurate, gives better semantics and all.
2. \[TypeScript tip\] ! for @resolve-ed fields is needed for strictPropertyInitialization / strict flags (which are highly recommended).
3. \[InversifyJS tip\] If you're binding against interface, then it might be more comfortable to collocate service identifier and type. With typed service identifier you get better type inference and less imports. Way better DX compared to using strings as identifiers.
`ts
export interface IFoo {
// ...
}
export namespace IFoo {
export const $: interfaces.ServiceIdentifier = Symbol('IFoo');
}
`
`ts
container.bind(IFoo.$).to(...);
// ^ no need to specify generic type,
// type gets inferred from explicit service identifier
`
`ts
// in constructor injections (not in React Components, but in services/stores/etc)
constructor(@inject(IFoo.$) foo: IFoo)
// in React Class component
@resolve(IFoo.$)
private readonly foo!: IFoo; // less imports and less chance of mix-up
// in functional component
const foo = useInjection(IFoo.$); // inferred as IFoo
``