在打字稿中与私有字段混合

Question

是否可以在 mixins 中使用私有字段？我想在内部保留一个字段，但 TS 编译器说 mixins 只能有 protected 或 private 字段。

ChatGPT 建议使用地图，这意味着每次我想使用该字段时都要查找。

type Constructor<T = {}> = new (...args: any[]) => T;

class BaseClass {
    name = "BaseClass";
}

function ExampleMixin<TBase extends Constructor>(Base: TBase) {
    return class extends Base {
        private secret: string = "This is private"; // Private field causing the export issue

        getSecret() {
            return this.secret;
        }
    };
}

// Attempt to export the mixin function
export const MixedClass = ExampleMixin(BaseClass);

Answer 1

如果您不想从 mixin 中公开任何内容，只需指定一个显式返回值（混合类是唯一的公共 API）：

type Constructor<T = {}> = new (...args: any[]) => T;

class BaseClass {
    name = "BaseClass";
}

//returns TBase
function ExampleMixin<TBase extends Constructor>(Base: TBase): TBase {
    return class extends Base {
        private secret: string = "This is private";

        getSecret() {
            return this.secret;
        }
    };
}

export const MixedClass = ExampleMixin(BaseClass);

如果你想从mixin中暴露部分API，定义一个接口并告诉返回值是类和接口的组合：

export interface PartialInterface
{
    publicProp: string;
}

function ExampleMixin<TBase extends Constructor>(Base: TBase): Constructor<PartialInterface> & TBase {
    return class extends Base {
        private secret: string = "This is private"; 
        publicProp = "hello";
        getSecret() {
            return this.secret;
        }
    };
}

export const MixedClass = ExampleMixin(BaseClass);