Simple TypeScript Template Literal Type usage for SQL query

sql-type.ts

type Split<S extends string, D extends string> = S extends `${infer T}${D}${infer U}` ? [T, ...Split<U, D>] : [S];
type Strip<S extends string> =
    S extends ` ${infer T}`
        ? Strip<T>
        : S extends `${infer U} `
        ? Strip<U>
        : S;

type MapStrip<A extends string[]> =
    A extends []
        ? A
        : A extends [string]
        ? [Strip<A[0]>]
        : A extends [string, ...infer R]
        ? [Strip<A[0]>, ...MapStrip<R>]
        : never;

type AsObject<A extends string[]> =
    A extends []
        ? {}
        : A extends [string]
        ? { [T in A[0]]: object }
        : A extends [string, ...infer R]
        ? { [T in A[0]]: object } & AsObject<R>
        : {}
type QueryResult<T extends string> = T extends `SELECT ${infer R} FROM` ? AsObject<MapStrip<Split<R, ",">>> : never;

declare function fetch<T extends string>(query: T): QueryResult<T>;

fetch("SELECT book_name, book_number FROM").book_name
fetch("SELECT book_name, book_number FROM").book_number
fetch("SELECT book_name, book_number FROM").book_numbera
fetch("SELECT book_name, book_number FROM").unknown_field