[英]Dynamic Dependency injection with Typescript using tsyringe
我正在嘗試構建和示例以了解 DI 框架/庫的工作原理,但我遇到了一些問題。
我有這個接口有兩種可能的實現:
export interface Operation {
calculate(a: number, b: number): number;
}
子.ts
import { Operation } from "./operation.interface";
export class Sub implements Operation {
calculate(a: number, b: number): number {
return Math.abs(a - b);
}
}
總和
import { Operation } from "./operation.interface";
export class Sum implements Operation {
calculate(a: number, b: number): number {
return a + b;
}
}
計算器.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);
}
}
索引.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 = ???
有沒有辦法讓我可以有兩個具有不同行為的計算器,或者我完全錯了?
由於OperationSub
未在任何地方使用,因此它不會影響注入的Operation
值。
具有不同依賴集的計算器應該用多個容器表示。 求和計算器可以被視為默認實現並使用根容器,或者兩種實現都可以由子容器表示,而根容器仍然是抽象的。
// 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);
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