分配条件类型 联合中的排序影响
Distributive conditional types Ordering influence in a union
类型
type Diff<T, U> = T extends U ? never : T;
来自documentationreturn类型联合的区别。为什么 f 的位置在类型中起作用？在以下示例中，我希望 f 是两种类型：
// f last position
type T30 = Diff<
"a" | "b" | "c" | "d",
"a" | "c" | "f"
>; //type is: "b" | "d"
// f first position
type T31 = Diff<
"f" | "a" | "b" | "c" | "d",
"a" | "c"
>; //type is: "b" | "d" | "f"
}
就像数学中的集合差；它给出了第一种类型的值，而第二种类型中没有。
类型
type Diff<T, U> = T extends U ? never : T;
来自documentationreturn类型联合的区别。为什么 f 的位置在类型中起作用？在以下示例中，我希望 f 是两种类型：
// f last position
type T30 = Diff<
"a" | "b" | "c" | "d",
"a" | "c" | "f"
>; //type is: "b" | "d"
// f first position
type T31 = Diff<
"f" | "a" | "b" | "c" | "d",
"a" | "c"
>; //type is: "b" | "d" | "f"
}
就像数学中的集合差；它给出了第一种类型的值，而第二种类型中没有。