typescript - 如何 console.log typescript 类型

Question

我知道 typescript 类型不是运行时变量。但是有什么解决方法可以打印类型名称和变量吗？

type TestDto = {
    active: number;  
    user_name: string;
};

console.log(TestDto);

扔 only refers to a type, but is being used as a value here.

Answer 1

来自 a comment :

I would like to create object property based on TS type. I would like to create JS object with property active and user_name with some default values.

您比基于类型创建对象更好的选择是做相反的事情并基于对象创建类型。这不仅为您提供了可以在运行时使用的具体内容，还可以作为属性的默认值:

const DefaultTestDto = {
    active: -1,
    user_name: "",
}

type TestDto = typeof DefaultTestDto;


const newDto1: TestDto = {...DefaultTestDto};
newDto1.user_name = "Fred";
//or
const newDto2: TestDto = Object.assign({}, DefaultTestDto, {user_name: "Barney"});

console.log(newDto1); // { "active": -1, "user_name": "Fred" } 
console.log(newDto2); // { "active": -1, "user_name": "Barney" }

Playground Link