使用 tsyringe 的 Typescript 动态依赖注入

Question

我正在尝试构建示例以了解 DI framework/library 的工作原理，但我遇到了一些问题。

我有这个接口有两种可能的实现：

export interface Operation {
    calculate(a: number, b: number): number;
}

sub.ts

import { Operation } from "./operation.interface";

export class Sub implements Operation {
    calculate(a: number, b: number): number {
        return Math.abs(a - b);
    }
}

sum.ts

import { Operation } from "./operation.interface";

export class Sum implements Operation {
    calculate(a: number, b: number): number {
        return a + b;
    }

}

calculator.ts

import { Operation } from "./operation.interface";
import {injectable, inject} from "tsyringe";

@injectable()
export class Calculator {
    constructor(@inject("Operation") private operation?: Operation){}

    operate(a: number, b: number): number {
        return this.operation.calculate(a, b);
    }
}

index.ts

import "reflect-metadata";
import { container } from "tsyringe";
import { Calculator } from "./classes/calculator";
import { Sub } from "./classes/sub";
import { Sum } from "./classes/sum";

container.register("Operation", {
    useClass: Sum
});

container.register("OperationSub", {
    useClass: Sub
});

const calculatorSum = container.resolve(Calculator);

const result = calculatorSum.operate(4,6);
console.log(result);

// const calculatorSub = ???

有没有办法让我拥有两个具有不同行为的计算器，还是我做的完全错了？

Answer 1

由于 OperationSub 没有在任何地方使用，它不会影响注入的 Operation 值。

具有不同依赖集的计算器应该用multiple containers表示。可以将求和计算器视为默认实现并使用根容器，或者两种实现都可以由子容器表示，而根容器保持抽象。

// common deps are registered on `container`
const sumContainer = container.createChildContainer();
const subContainer = container.createChildContainer();

sumContainer.register("Operation", { useClass: Sum });  
subContainer.register("Operation", { useClass: Sub });

const calculatorSum = sumContainer.resolve(Calculator);
const calculatorSub = subContainer.resolve(Calculator);

使用 tsyringe 的 Typescript 动态依赖注入

Dynamic Dependency injection with Typescript using tsyringe

node.js

typescript

dependency-injection

tsyringe