Typescript变量可以是任意一种类型

我有一个

packageMessage

工厂函数，需要它根据

type

参数的值返回两种类型中的一种：

PackagedChannel

或

packagedbuildchannel

功能：

function packageMessage(id: string, type: PackagedChannelType, name?: string, position?: number): PackagedChannel | PackagedGuildChannel {
    var packaged: PackagedChannel | PackagedGuildChannel;
    packaged.id = id;
    packaged.type = type;
    if (type === 'text') {
        packaged.name = name;
        packaged.position = position;
    }
    return packaged;
}

type PackagedChannelType = 'dm' | 'text' | 'unknown';
interface PackagedChannel {
    id: string;
    type: PackagedChannelType;
}
interface PackagedGuildChannel extends PackagedChannel {
    name: string;
    position: number;
}

类型：

function packageMessage(id: string, type: PackagedChannelType, name?: string, position?: number): PackagedChannel | PackagedGuildChannel {
    var packaged: PackagedChannel | PackagedGuildChannel;
    packaged.id = id;
    packaged.type = type;
    if (type === 'text') {
        packaged.name = name;
        packaged.position = position;
    }
    return packaged;
}

type PackagedChannelType = 'dm' | 'text' | 'unknown';
interface PackagedChannel {
    id: string;
    type: PackagedChannelType;
}
interface PackagedGuildChannel extends PackagedChannel {
    name: string;
    position: number;
}

但是，该函数生成的

属性“name/position”在类型“PackagedChannel”上不存在
错误

我该怎么做？非常感谢您的帮助：）

或者更好的是，如果您想要更多的类型安全性，您可能会使其过载

function packageMessage(id: string, type: 'text', name: string, position: number): PackagedGuildChannel

function packageMessage(id: string, type: 'dm' | 'unknown'): PackagedChannel

function packageMessage(id: string, type: PackagedChannelType, name?: string, position?: number): PackagedChannel | PackagedGuildChannel

function packageMessage(id: string, type: PackagedChannelType, name?: string, position?: number): PackagedChannel | PackagedGuildChannel {
    return type === 'text' ? { id, type, name, position } : { id, type };
}

（现在好多了）