Type Alias Alphabet

Alphabet: LowerAlphabet | UpperAlphabet

Represents the set of both lowercase and uppercase English alphabet letters. A union of LowerAlphabet and UpperAlphabet, covering all 52 English letters.

Useful for general alphabetic character validation, text processing, and type-safe operations that work with any English letter.

Example

type AlphabetCount = 52; // LowerAlphabet (26) + UpperAlphabet (26)

const isAlphabetic = (char: string): char is Alphabet => {
  return char.length === 1 &&
         ((char >= 'a' && char <= 'z') || (char >= 'A' && char <= 'Z'));
};

type ExtractAlpha<S extends string> = S extends `${infer F}${infer R}`
  ? F extends Alphabet
    ? `${F}${ExtractAlpha<R>}`
    : ExtractAlpha<R>
  : '';

type OnlyLetters = ExtractAlpha<'H3ll0 W0rld!'>; // 'HllWorld'

Type Alias Alphabet

Example

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