romanize-string/dist/esm/vendor/romanize/korean/src/index.js

A fully typed, general-purpose utility for unidirectional string transliteration (non-Latin script => Latin script).

import { REVISED_ROMANIZATION_OF_KOREAN } from "./constants/revised.js";
import { HangulSyllable } from "./lib/decompose-hangul.js";
import { HangulTree } from "./lib/is-hangul.js";
const tree = new HangulTree();
function separate(hangul) {
    if (!tree.isHangul(hangul)) {
        throw new Error("Not a Hangul string");
    }
    const chars = hangul.split("").reduce((list, char) => {
        const result = tree.search(char.charCodeAt(0));
        const block = result.length === 1 ? result[0].value : null;
        switch (block) {
            case "HANGUL_SYLLABLES":
                const syllable = new HangulSyllable(char);
                const { initial, medial, final } = syllable;
                if (final !== "") {
                    return list.concat([initial, medial, final]);
                }
                return list.concat([initial, medial]);
            case null:
            default:
                return list.concat([char]);
        }
    }, []);
    return chars;
}
function convert(chars, system) {
    let res = "";
    for (let i = 0; i < chars.length; i++) {
        if (chars[i] in system) {
            const c = chars[i];
            if (system[c].next &&
                i + 1 < chars.length &&
                chars[i + 1] in system) {
                const nextC = chars[i + 1];
                if (nextC in system[c].next) {
                    const nextInitial = nextC;
                    res += system[c].next[nextInitial];
                    i++;
                    continue;
                }
            }
            res += system[c].base;
            continue;
        }
        res += chars[i];
    }
    return res;
}
export function romanize(hangul) {
    const chars = separate(hangul);
    return convert(chars, REVISED_ROMANIZATION_OF_KOREAN);
}