類型別名 CapitalizeKeys<T>

CapitalizeKeys: Capitalize<keyof T & string>

TypeScript 類型，替換成大寫開頭的 T 的所有屬性鍵

type CamelCase = { fooFoo: number, bazBaz: { barBar: number } };
type PascalKeys = CapitalizeKeys<CamelCase> // => "FooFoo" | "BazBaz";