我正在尝试使用泛型根据输入的特定形状缩小函数的返回类型。这在 TypeScript 中可能吗?我有以下 MRE 演示了该问题:
type ValidInput = {
filename: string;
sender: number;
};
type ValidInput2 = {
person: string;
sender: string;
};
type InferSenderType<T extends { sender: any }> = T extends { sender: infer K }
? K
: unknown;
type Api<I extends { sender: any }> = (input: I) => InferSenderType<I>;
declare const loadFile: Api<ValidInput | ValidInput2>;
const a = loadFile({ filename: "q", sender: 3 });
typeof a // string | number
// How do I get it to narrow the return type (in this case 'number') based on the input?
最佳答案
这是一个例子:
type ValidInput = {
filename: string;
sender: number;
};
type ValidInput2 = {
person: string;
sender: string;
};
type Api = <I extends { sender: any }>(input: I) => I['sender']
declare const loadFile: Api;
const a = loadFile({ filename: "q", sender: 3 });
typeof a // only number
关于typescript - 使用泛型基于输入的窄返回类型,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/66205700/