解决字面量类型推断错误的四种方式
- 方式一：对象属性使用类型断言
- 方式二：传参使用类型断言
- 方式三：对象使用类型断言
- 方式四：对象属性使用变量，变量使用字面量类型
- 参考
declare function handleRequest(url: string, method: "GET" | "POST"): void;
const req = { url: "https://www.baidu.com", method: "GET" }
handleRequest(req.url, req.method);
报错如下
方式一：对象属性使用类型断言
declare function handleRequest(url: string, method: "GET" | "POST"): void;
const req = { url: "https://www.baidu.com", method: "GET" as "GET" };
handleRequest(req.url, req.method);
方式二：传参使用类型断言
declare function handleRequest(url: string, method: "GET" | "POST"): void;
const req = { url: "https://www.baidu.com", method: "GET" };
handleRequest(req.url, req.method as "GET");
方式三：对象使用类型断言
declare function handleRequest(url: string, method: "GET" | "POST"): void;
const req = { url: "https://www.baidu.com", method: "GET" } as const;
handleRequest(req.url, req.method);
方式四：对象属性使用变量，变量使用字面量类型
declare function handleRequest(url: string, method: "GET" | "POST"): void;
const method: "GET" | "POST" = "GET";
const req = { url: "https://www.baidu.com", method };
handleRequest(req.url, req.method);
参考
literal-inference
unit-types
