TypeScript 类装饰器 - 添加类方法 [英] TypeScript class decorators - add class method

问题描述

如何使用 TypeScript 和装饰器定义属性?

How to define property with TypeScript and decorators?

例如我有这个类装饰器:

For example I have this class decorator:

function Entity<TFunction extends Function>(target: TFunction): TFunction {
    Object.defineProperty(target.prototype, 'test', {
        value: function() {
            console.log('test call');
            return 'test result';
        }
    });
    return target;
}

并使用它:

@Entity
class Project {
    //
}

let project = new Project();
console.log(project.test());

我有这个控制台日志:

test call            entity.ts:5
test result          entity.ts:18

此代码正确运行，但 tsc 返回错误:

This code correctly worked, but tsc return error:

entity.ts(18,21): error TS2339: Property 'test' does not exist on type 'Project'.

如何修复这个错误?

推荐答案

据我所知，目前这是不可能的.这里有一个关于这个问题的讨论:issue.

Af far as I know for now this is not possible. There is a discussion on this issue here: issue.

因此，您要么不使用装饰器来扩展类，要么在适当的情况下使用带有声明合并的接口来扩展类型声明.或者使用类型断言(但会丢失类型检查):(project).test()

So you either do not use decorators to extend classes, and maybe if appropriate use interfaces with declaration merging to extend type declaration. Or use type assertion (but loosing type checks): (<any>project).test()

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