Convert string[] literal to string type literal
问题 I have an array of strings: let foo = ["bar", "baz"]; I wish to perform something similar to keyof type foo , but for an array rather than an object: type DESIRED_RESULT = "bar"|"baz"; Is there any way to convert all unique strings within an array to a type? 回答1: foo is inferred as string[] . The array values don't enter the type system at all, so this is impossible. If you put it in the type system, it becomes possible: let foo: ["bar", "baz"]; let bar: typeof foo[number] = ""; Type '""' is