di-container-js

DI container

Dependency injection library for js with zero dependencies

Basic usage

import DiContainer from "di-container-js";
// OR
const DiContainer = require("di-container-js").DiContainer;

let diContainer = new DiContainer();

const componentRef1 = Symbol(),
    componentRef2 = "component2";

class Component2 {
    // define `static dependencies()` method in your class to specify what dependencies are needed
    // otherwise required dependecies will be resolved from constructor arguments
    static dependencies() {
        return [componentRef1];
    }

    constructor(component1) {
        this.component1 = component1;
    }
}

class Component1 {
    constructor() {
    }
}


diContainer.registerClass(componentRef1, Component1);
diContainer.registerClass(componentRef2, Component2);

(async () => {
    // .get method returns promise resolved to dependency instance
    let component2Instance = await diContainer.get(componentRef2);
    // now component2Instance has component1 assigned to it
})();

You can also inject diContainer itself to any component:

constructor(diContainer, ...) {
    this.diContainer = diContainer;
    ...
}

Providing configuration

...

class TestClass {

    constructor() {
    }

    postConstruct(config) {
        // gets called by DI container after instance created
        // can return promise, in this case DI container will
        // wait until promise resolved
        return Promise.resolved();
    }

}

let diContainer = new DiContainer();
// pass configuration as third parameter to .registerClass
diContainer.registerClass("testDependency", TestClass, {configKey: "configValue"});
// OR
// provide config using .configure method
diContainer.configure("testDependency", {configKey: "configValue"});

(async () => {
    let testDependency = await diContainer.get("testDependency");
    // do something
})();

Usage with React

To use dependency injection with React class components you should have a custom ComponentProvider. Unlike default one, it should construct a react component instead of an instance of a class. There is a useful example of inject() decorator function which uses the custom component provider ReactProvider and InjectionHoc high-order component to add dependency injection functionality to React class components. Usage:

import {inject} from '../../di/inject';

class MyComponent extends React.Component {
    
    static dependencies() {
        return [/*...*/];
    }


}

export default inject(MyComponent);

API Reference

DiContainer

register(componentRef, componentProvider)

Register a dependency using the ComponentProvider

registerClass(componentRef, classRef, [config])

Register a dependency using a class reference

provide(componentRef, instance)

Provide a component instance

configure(componentRef, config, mergeConfig)

Sets a configuration object which will be passed to 'postConstruct' method of a component

get(componentRef) ⇒ Promise.<any>

Retrieve a component instance

constructExternal(classRef, config) ⇒ Promise.<(*|undefined)>

Construct an instance of a class without registration in the DI container

constructExternalUsingProvider(provider) ⇒ Promise.<(*|un defined)>

Construct a component without registration in the DI container

createFactory(classRef) ⇒ Promise.<ComponentFactory>

Create a factory for a class. A factory allows to create multiple instances of a class and inject dependencies to them. A factory itself is not registered in DI container

isInitialized(componentRef) ⇒ boolean

isProvided(componentRef) ⇒ boolean

register(componentRef, componentProvider)

Register a dependency using the ComponentProvider

Param	Type	Description
componentRef	symbol | string	dependency identifier
componentProvider	ComponentProvider	provider which is used to construct a dependency instance

registerClass(componentRef, classRef, [config])

Register a dependency using a class reference

Param	Type	Description
componentRef	symbol | string	dependency identifier
classRef	function	reference to a class
[config]	object	configuration object which is passed to the postConstruct method of a class after
it's creation

provide(componentRef, instance)

Provide a component instance

Param	Type
componentRef	symbol | string
instance	any

configure(componentRef, config, mergeConfig)

Sets a configuration object which will be passed to 'postConstruct' method of a component

Param	Type	Default	Description
componentRef	symbol | string
config	object
mergeConfig	boolean	true	whenever merge new config to old one

get(componentRef) ⇒ Promise.<any>

Retrieve a component instance

Param	Type
componentRef	symbol | string

constructExternal(classRef, config) ⇒ Promise.<(*|undefined)>

Construct an instance of a class without registration in the DI container

Param	Type
classRef	function
config	object

constructExternalUsingProvider(provider) ⇒ Promise.<(*|undefined)>

Construct a component without registration in the DI container

Param	Type
provider	ComponentProvider

createFactory(classRef) ⇒ Promise.<ComponentFactory>

A factory itself is not registered in DI container class and inject dependencies to them.

Param	Type
classRef	function

isInitialized(componentRef) ⇒ boolean

Param	Type
componentRef	symbol | string

isProvided(componentRef) ⇒ boolean

Param	Type
componentRef	symbol | string