/** An encoding/decoding alphabet using the numbers 0-9. */
export declare const decimal = "0123456789";
/** An encoding/decoding alphabet using ASCII letters only (no numbers). */
export declare const alpha = "abcdefghijklmnopqrstuvwxyz";
/**
 * An encoding/decoding alphabet using decimal numbers and lowercase letters.
 */
export declare const base36 = "0123456789abcdefghijklmnopqrstuvwxyz";
/**
 * An encoding/decoding alphabet using decimal numbers, lowercase letters,
 * uppercase letters, underscores, and dashes.
 */
export declare const base64 = "0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ_-";
/**
 * An encoding/decoding alphabet similar to base64, but with some letters and
 * numbers strategically removed to improve readability (avoids lookalike
 * characters) and curb accidental profanity.
 */
export declare const base48Safe = "2345679bcdfghjkmnpqrstvwxyzBCDFGHJKLMNPQRSTVWXYZ";
/**
 * Encodes/decodes a string from the given "from" alphabet to the given "to"
 * alphabet. The process is symmetric, so to decode the string, call the same
 * function with the "from" and "to" alphabets swapped. Throws an error if a
 * character within the input string is not in the "from" alphabet.
 * @param input The string to encode/decode.
 * @param fromAlpha The alphabet the input string is using, e.g. decimal.
 * @param toAlpha The alphabet the output string should use, e.g. base-64.
 */
export declare function reencode(input: string, fromAlpha: string, toAlpha: string): string;
/**
 * Encodes/decodes a string from the given "from" alphabet to the given "to"
 * alphabet. The process is symmetric, so to decode the string, call the same
 * function with the "from" and "to" alphabets swapped. Returns null if a
 * character within the input string is not in the "from" alphabet.
 * @param input The string to encode/decode.
 * @param fromAlpha The alphabet the input string is using, e.g. decimal.
 * @param toAlpha The alphabet the output string should use, e.g. base-64.
 */
export declare function tryReencode(input: string, fromAlpha: string, toAlpha: string): string | null;