可以使用數組值來創建具有相應字符串文字的鍵值類型嗎？

Question

//### Desired Implementation & Outcome: ###// function objectFromArray<T extends string[]>(...arr:T){ return {/* do things */} as ObjectFromArray<T> } const foo = objectFromArray("a", "b", "c") // foo === {a:"a", b:"b", c:"c"} // typeof foo.a === "a" // typeof foo.b === "b" // typeof foo.c === "c" //### Attempt 1: ###// type ObjectFromArray<T extends any[]> = {[K in T[number]]: T[number]} // no error, but results in unions instead of single values: // typeof foo.a === ("a" | "b" | "c") // typeof foo.b === ("a" | "b" | "c") // typeof foo.c === ("a" | "b" | "c") //### Attempt 2: ###// type ObjectFromArray<T extends string[]> = {[K in T[number]]: T[number][K]} // Error: Type 'K' cannot be used to index type 'T[number]'.ts(2536)

Answer 1

希望這就是你的意思：

function objectFromArray<T extends string[]>(...arr:T){
    return {/* do things */} as ObjectFromArray<T>
}

type ObjectFromKeyList<KeyList extends string> = {[K in KeyList]: K}
type ArrayToKeyList<T extends any[]> = T extends (infer P)[] ? P : never
type ObjectFromArray<T extends any[]> = ObjectFromKeyList<ArrayToKeyList<T>>

const foo = objectFromArray("a", "b", "c")

foo.a // type is 'a'