Kanji numerals

import { … } from "@johnmorrisdotca/hikidashi/numerals";

漢数字: numbers, in both directions between the two ways of writing them.

一億二千万 is a number a learner meets in a news headline and cannot read, and 120,000,000 is a number they can read and cannot write. Japanese counts in ten-thousands rather than thousands (万, 億, 兆, each one 10,000 times the last), which is why 120 million is "twelve thousand ten-thousands" and why reading one off a page is a different skill from reading the digits. That grouping is the whole of this module.

• parseJapaneseNumber reads 一億二千万, 1億2000万, 2万5千 or 120000000 and gives 120000000, or null.
• writeJapaneseNumber writes it back, and with formal the way a contract or a banknote does: 壱万.
• readJapaneseNumber says it aloud in hiragana, with the sound changes (さんびゃく, はっぴゃく).
• parseEnglishNumber reads "five hundred", "twenty-five" and the magnitudes in romaji ("5 man").

Whole numbers from 0 to 9,007,199,254,740,991 only: past that JavaScript stops counting exactly, and a number the runtime cannot hold is worse than one that is not offered.