TypeScriptで簡単なDI

はじめに

シンプルにDIがやりたかった。

DIコンテナつくる

Dependencies.ts

type Class<T> = new() => T

export default class Dependencies {

    static container: Map<Class<any>, any> = new Map()

    static inject<T>(clazz: Class<T>): T {
        const instance = Dependencies.container.get(clazz)
        if (instance) {
            return instance
        }
        const newInstance = new clazz()
        Dependencies.container.set(clazz, newInstance)
        return newInstance
    }
}

使う

import Dependencies from "./Dependencies";

class Test {} // Singletonにしたいクラス

const val1 = Dependencies.inject(Test)
const val2 = Dependencies.inject(Test)
console.log(val1 === val2) // true