Number Base Converter — TypeScript source

// Arbitrary-precision base conversion (BigInt). Bases 2-36. Pure + deterministic
// - the unit-test surface for the Number Base Converter tool.
// Digit math lives in bigintBaseCore; this module defines the null-on-failure
// contract (prefixes stripped only when they match the base).

import { parseDigits, formatDigits } from './bigintBaseCore';

export function parseBigInt(str: string, base: number): bigint | null {
  const r = parseDigits(str, base, { strictPrefix: true });
  return r.ok ? r.value : null;
}

export function formatBigInt(value: bigint, base: number): string {
  return formatDigits(value, base, {});
}

export function convertBase(value: string, fromBase: number, toBase: number): string | null {
  const n = parseBigInt(value, fromBase);
  if (n === null) return null;
  return formatBigInt(n, toBase);
}

export interface BaseRow {
  base: number;
  text: string;
}

const ALL_BASES_DEFAULT = [2, 8, 10, 16, 32, 36];

/** The bases the all-bases panel shows — exported for callers that already
 *  hold a parsed BigInt and want the rows without re-parsing (single-parse
 *  pattern in the island). */
export const DEFAULT_BASES = ALL_BASES_DEFAULT;

/** The same value rendered in several bases at once (live all-bases view).
 *  Returns null when the input does not parse in fromBase. */
export function allBases(value: string, fromBase: number, bases: number[] = ALL_BASES_DEFAULT): BaseRow[] | null {
  const n = parseBigInt(value, fromBase);
  if (n === null) return null;
  return bases.map((base) => ({ base, text: formatBigInt(n, base) }));
}