Japanese‑numerals‑to‑number is a small Node.js library that parses Japanese numeral strings—including standard, positional, and formal (daiji) forms—and returns their numeric value as a JavaScript `Number` (up to `Number.MAX_SAFE_INTEGER`). It validates input, throws helpful errors for invalid strings or non‑string arguments, and is intended for developers who need to convert Japanese written numbers (e.g., “一億二千三百四十五万六千七百八十九”) into plain numbers in their applications.