Types for checking if phone is in E164 format

E164format.ts

type Digit = "1" | "2" | "3" | "4" | "5" | "6" | "7" | "8" | "9" | "0";

type EveryOfType<A extends readonly any[], T> = keyof {
  [P in Exclude<keyof A, keyof any[]> as A[P] extends T ? never : P]: P;
} extends never
  ? true
  : false;

type SplitString<
  T extends string,
  A extends string[] = []
> = T extends `${infer F}${infer L}` ? SplitString<L, [...A, F]> : A;

type E164Format<T extends string> = SplitString<T> extends [
  "+",
  Digit,
  Digit,
  Digit,
  ...infer L
]
  ? L["length"] extends 12
    ? EveryOfType<L, Digit> extends true
      ? T
      : never
    : never
  : never;

type testOK = E164Format<"+191012345678910">; //"+191012345678910"
type testLen = E164Format<"+19101234567891">; //never, 11 digits after
type testType = E164Format<"+1910123456B8910">; //never, "B" encountered