Press n or j to go to the next uncovered block, b, p or k for the previous block.
| 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 | 4x 4x 4x 4x 4x 4x 4x 4x 4x 28x 4x 4x 44x 319x 69x 143x 97x 97x 49x 49x 48x 7x 46x 162x 92x 70x 18x 2x 147x 136x 136x 1x 135x 135x 135x 74x 74x 38x 36x 1x 1x 35x 25x 7x 7x 7x 18x 18x 10x 10x 7x 3x 3x 3x 3x 61x 61x 46x 15x 8x 8x 7x 1x 1x 1x 7x 7x 2x 2x 2x 5x 5x 7x 7x 135x 2x 9x 9x 8x 8x 3x 3x 5x 3x 3x 2x 8x 4x 92x | import type { Composer, ComposerResult, ComposerState } from "../types";
// ============================================================================
// Hangul 두벌식 (dubeolsik) composer
// ----------------------------------------------------------------------------
// A finite-state 한글 오토마타 that combines a stream of compatibility jamo
// (ㄱ, ㅏ, ㅐ, …) into complete syllable blocks (가, 각, 값, 과, …). It handles
// the four hard cases: initial/medial/final assembly, compound vowels (ㅗ+ㅏ→ㅘ),
// compound finals (ㄱ+ㅅ→ㄳ), and final→initial migration when a vowel follows a
// completed block (강+ㅏ → 가+ㅏ → …, 값+ㅏ → 갑+사).
//
// State is carried entirely in `ComposerState.buffer` as the *rendered* in-progress
// syllable (e.g. "각" or a lone "ㄱ"/"ㅏ"), so the interface stays the plain
// `{ buffer: string }` and every step is a pure function of (buffer, key).
// ============================================================================
/** Compatibility-jamo tables, indexed as the Unicode syllable composition expects. */
// prettier-ignore
const CHO = ["ㄱ","ㄲ","ㄴ","ㄷ","ㄸ","ㄹ","ㅁ","ㅂ","ㅃ","ㅅ","ㅆ","ㅇ","ㅈ","ㅉ","ㅊ","ㅋ","ㅌ","ㅍ","ㅎ"]; // 19 initials
// prettier-ignore
const JUNG = ["ㅏ","ㅐ","ㅑ","ㅒ","ㅓ","ㅔ","ㅕ","ㅖ","ㅗ","ㅘ","ㅙ","ㅚ","ㅛ","ㅜ","ㅝ","ㅞ","ㅟ","ㅠ","ㅡ","ㅢ","ㅣ"]; // 21 medials
// prettier-ignore
const JONG = ["","ㄱ","ㄲ","ㄳ","ㄴ","ㄵ","ㄶ","ㄷ","ㄹ","ㄺ","ㄻ","ㄼ","ㄽ","ㄾ","ㄿ","ㅀ","ㅁ","ㅂ","ㅄ","ㅅ","ㅆ","ㅇ","ㅈ","ㅊ","ㅋ","ㅌ","ㅍ","ㅎ"]; // 28 finals (index 0 = none)
const HANGUL_BASE = 0xac00; // '가'
const HANGUL_LAST = 0xd7a3; // '힣'
/** Two single vowels that merge into a compound medial, keyed by `base + added`. */
// prettier-ignore
const JUNG_COMBINE: Record<string, number> = {
"ㅗㅏ": 9, "ㅗㅐ": 10, "ㅗㅣ": 11, // ㅘ ㅙ ㅚ
"ㅜㅓ": 14, "ㅜㅔ": 15, "ㅜㅣ": 16, // ㅝ ㅞ ㅟ
"ㅡㅣ": 19, // ㅢ
};
/** A single final + a consonant that merge into a compound final, keyed by `final + cons`. */
// prettier-ignore
const JONG_COMBINE: Record<string, number> = {
"ㄱㅅ": 3, // ㄳ
"ㄴㅈ": 5, "ㄴㅎ": 6, // ㄵ ㄶ
"ㄹㄱ": 9, "ㄹㅁ": 10, "ㄹㅂ": 11, "ㄹㅅ": 12, "ㄹㅌ": 13, "ㄹㅍ": 14, "ㄹㅎ": 15, // ㄺ ㄻ ㄼ ㄽ ㄾ ㄿ ㅀ
"ㅂㅅ": 18, // ㅄ
};
/** Inverse of {@link JUNG_COMBINE}: compound medial index → base medial index. */
const JUNG_DECOMPOSE: Record<number, number> = {};
for (const [pair, idx] of Object.entries(JUNG_COMBINE)) {
JUNG_DECOMPOSE[idx] = JUNG.indexOf(pair[0]);
}
/** Inverse of {@link JONG_COMBINE}: compound final index → `[keptFinalChar, migratingConsonant]`. */
const JONG_DECOMPOSE: Record<number, [string, string]> = {};
for (const [pair, idx] of Object.entries(JONG_COMBINE)) {
JONG_DECOMPOSE[idx] = [pair[0], pair[1]];
}
const isConsonant = (ch: string): boolean => CHO.includes(ch);
const isVowel = (ch: string): boolean => JUNG.includes(ch);
/** A decomposed in-progress syllable. `cho`/`jung` are `-1` when absent; `jong` is `0` when absent. */
interface Syllable {
cho: number;
jung: number;
jong: number;
}
/** Parse the buffer (a syllable, a lone jamo, or "") back into its components. */
function decompose(buffer: string): Syllable {
if (buffer.length === 1) {
const code = buffer.charCodeAt(0);
if (code >= HANGUL_BASE && code <= HANGUL_LAST) {
const s = code - HANGUL_BASE;
return { cho: Math.floor(s / 588), jung: Math.floor((s % 588) / 28), jong: s % 28 };
}
if (isConsonant(buffer)) return { cho: CHO.indexOf(buffer), jung: -1, jong: 0 };
Eif (isVowel(buffer)) return { cho: -1, jung: JUNG.indexOf(buffer), jong: 0 };
}
return { cho: -1, jung: -1, jong: 0 };
}
/** Render a decomposed syllable back to a string (full block, lone jamo, or ""). */
function compose({ cho, jung, jong }: Syllable): string {
if (cho >= 0 && jung >= 0) {
return String.fromCharCode(HANGUL_BASE + cho * 588 + jung * 28 + jong);
}
if (cho >= 0) return CHO[cho];
if (jung >= 0) return JUNG[jung];
return "";
}
const result = (committed: string, composing: string): ComposerResult => ({
committed,
composing,
next: { buffer: composing },
});
/** Apply one compatibility jamo (or any other char) to the current composing buffer. */
function input(state: ComposerState, key: string): ComposerResult {
const buffer = state.buffer ?? "";
// Anything that is not a jamo (digit, space, punctuation) flushes the pending
// syllable and commits itself — matching how an OS IME behaves.
if (!isConsonant(key) && !isVowel(key)) {
return result(buffer + key, "");
}
const s = decompose(buffer);
let committed = "";
if (isConsonant(key)) {
const asJong = JONG.indexOf(key); // -1 for ㄸ/ㅃ/ㅉ (never valid finals)
if (s.cho < 0 && s.jung < 0) {
// Empty buffer → begin a new syllable with this initial.
s.cho = CHO.indexOf(key);
} else if (s.jung < 0) {
// Two consonants with no vowel between them: commit, restart.
committed = compose(s);
s.cho = CHO.indexOf(key);
} else if (s.jong === 0) {
if (s.cho < 0) {
// A lone medial (vowel with no initial) can't take a final → commit it
// and let this consonant lead a new syllable.
committed = compose(s);
s.cho = CHO.indexOf(key);
s.jung = -1;
} else if (asJong > 0) {
s.jong = asJong; // consonant becomes the final
} else E{
committed = compose(s); // ㄸ/ㅃ/ㅉ can't be a final → commit, restart
s.cho = CHO.indexOf(key);
s.jung = -1;
}
} else {
const combined = JONG_COMBINE[JONG[s.jong] + key];
if (combined) {
s.jong = combined; // ㄱ + ㅅ → ㄳ, …
} else {
committed = compose(s); // final already set/incompatible → commit, restart
s.cho = CHO.indexOf(key);
s.jung = -1;
s.jong = 0;
}
}
} else {
const vIdx = JUNG.indexOf(key);
if (s.jung < 0) {
// Empty buffer or lone initial → attach the medial (가, or a lone ㅏ).
s.jung = vIdx;
} else if (s.jong === 0) {
const combined = JUNG_COMBINE[JUNG[s.jung] + key];
if (combined !== undefined) {
s.jung = combined; // ㅗ + ㅏ → ㅘ, …
} else {
committed = compose(s); // two medials that don't merge → commit, new lone vowel
s.cho = -1;
s.jung = vIdx;
}
} else {
// A vowel after a completed block: the final migrates to lead a new syllable.
const split = JONG_DECOMPOSE[s.jong];
if (split) {
const [keep, move] = split;
committed = compose({ cho: s.cho, jung: s.jung, jong: JONG.indexOf(keep) });
s.cho = CHO.indexOf(move);
} else {
committed = compose({ cho: s.cho, jung: s.jung, jong: 0 });
s.cho = CHO.indexOf(JONG[s.jong]);
}
s.jung = vIdx;
s.jong = 0;
}
}
return result(committed, compose(s));
}
/** Flush the pending syllable into committed text (called on space/enter). */
function flush(state: ComposerState): ComposerResult {
return result(state.buffer ?? "", "");
}
/** Delete the last jamo of the composing syllable (compound-aware), committing nothing. */
function backspace(state: ComposerState): ComposerResult {
const buffer = state.buffer ?? "";
if (buffer === "") return result("", "");
const s = decompose(buffer);
if (s.jong !== 0) {
const split = JONG_DECOMPOSE[s.jong];
s.jong = split ? JONG.indexOf(split[0]) : 0; // ㄳ → ㄱ, else drop the final
} else if (s.jung >= 0) {
const base = JUNG_DECOMPOSE[s.jung];
s.jung = base !== undefined ? base : -1; // ㅘ → ㅗ, else drop the medial
} else {
s.cho = -1; // drop the lone initial
}
return result("", compose(s));
}
/**
* The Korean **두벌식 (dubeolsik)** IME composer — an opt-in {@link Composer} that
* assembles compatibility jamo into Hangul syllable blocks with full support for
* compound vowels/finals and final→initial migration.
*
* Attach it to a layout (see {@link hangulLayout}) or pass it directly; the
* {@link VirtualKeyboard} renders the returned `composing` text as an underlined
* pending block until it is committed (on the next block, space, or enter).
*
* @example
* ```ts
* import { hangulComposer } from "@usefy/virtual-keyboard/hangul";
*
* let s = hangulComposer.reset();
* let r = hangulComposer.input(s, "ㄱ"); // { committed: "", composing: "ㄱ" }
* r = hangulComposer.input(r.next, "ㅏ"); // { committed: "", composing: "가" }
* r = hangulComposer.input(r.next, "ㅁ"); // { committed: "", composing: "감" }
* r = hangulComposer.flush(r.next); // { committed: "감", composing: "" }
* ```
*/
export const hangulComposer: Composer = {
input,
flush,
backspace,
reset() {
return { buffer: "" };
},
};
|