opencc-js
Version:
The JavaScript version of Open Chinese Convert (OpenCC)
293 lines (268 loc) • 8.45 kB
JavaScript
/**
* 字典，範例："a alpha|b beta" 或 [["a", "alpha"], ["b", "beta"]]
* @typedef {string|string[][]} DictLike
*/
/**
* 字典群組
* @typedef {DictLike[]} DictGroup
*/
/**
* 地區設定資料
* @typedef {object} LocalePreset
* @property {object.<string, DictGroup>} from
* @property {object.<string, DictGroup>} to
*/
/**
* Trie 樹。
*/
export class Trie {
// 使用 Map 實作 Trie 樹
// Trie 的每個節點為一個 Map 物件
// key 為 code point，value 為子節點（也是一個 Map）。
// 如果 Map 物件有 trie_val 屬性，則該屬性為值字串，代表替換的字詞。
constructor() {
this.map = new Map();
}
/**
* 將一項資料加入字典樹
* @param {string} s 要匹配的字串
* @param {string} v 若匹配成功，則替換為此字串
*/
addWord(s, v) {
let { map } = this;
for (const c of s) {
const cp = c.codePointAt(0);
const nextMap = map.get(cp);
if (nextMap == null) {
const tmp = new Map();
map.set(cp, tmp);
map = tmp;
} else {
map = nextMap;
}
}
map.trie_val = v;
}
/**
* 讀取字典資料
* @param {DictLike} d 字典
*/
loadDict(d) {
if (typeof d === 'string') {
d = d.split('|');
for (const line of d) {
const [l, r] = line.split(' ');
this.addWord(l, r);
}
} else {
for (let arr of d) {
const [l, r] = arr;
this.addWord(l, r);
}
}
}
/**
* 讀取多個字典資料
* @param {DictLike[]} arr 字典
*/
loadDictGroup(arr) {
arr.forEach(d => {
this.loadDict(d);
});
}
/**
* 根據字典樹中的資料轉換字串。
* @param {string} s 要轉換的字串
*/
convert(s) {
const t = this.map;
const n = s.length, arr = [];
let orig_i;
for (let i = 0; i < n;) {
let t_curr = t, k = 0, v;
for (let j = i; j < n;) {
const x = s.codePointAt(j);
j += x > 0xffff ? 2 : 1;
const t_next = t_curr.get(x);
if (typeof t_next === 'undefined') {
break;
}
t_curr = t_next;
const v_curr = t_curr.trie_val;
if (typeof v_curr !== 'undefined') {
k = j;
v = v_curr;
}
}
if (k > 0) { // 有替代
if (orig_i !== null) {
arr.push(s.slice(orig_i, i));
orig_i = null;
}
arr.push(v);
i = k;
} else { // 無替代
if (orig_i === null) {
orig_i = i;
}
i += s.codePointAt(i) > 0xffff ? 2 : 1;
}
}
if (orig_i !== null) {
arr.push(s.slice(orig_i, n));
}
return arr.join('');
}
}
/**
* Create a OpenCC converter
* @param {...DictGroup} dictGroup
* @returns The converter that performs the conversion.
*/
export function ConverterFactory(...dictGroups) {
const trieArr = dictGroups.map(grp => {
const t = new Trie();
t.loadDictGroup(grp);
return t;
});
/**
* The converter that performs the conversion.
* @param {string} s The string to be converted.
* @returns {string} The converted string.
*/
function convert(s) {
return trieArr.reduce((res, t) => {
return t.convert(res);
}, s);
}
return convert;
}
/**
* Build Converter function with locale data
* @param {LocalePreset} localePreset
* @returns Converter function
*/
export function ConverterBuilder(localePreset) {
return function Converter(options) {
let dictGroups = [];
['from', 'to'].forEach(type => {
if (typeof options[type] !== 'string') {
throw new Error('Please provide the `' + type + '` option');
}
if (options[type] !== 't') {
dictGroups.push(localePreset[type][options[type]]);
}
});
return ConverterFactory.apply(null, dictGroups);
}
}
/**
* Create a custom converter.
* @param {string[][]} dict The dictionary to be used for conversion.
* @returns The converter that performs the conversion.
*/
export function CustomConverter(dict) {
return ConverterFactory([dict]);
}
/**
* Create a HTML page converter.
* @param {(s: string) => string} converter The converter that performs the conversion.
* @param {HTMLElement} rootNode The root node for recursive conversions.
* @param {string} fromLangTag The lang tag to be converted.
* @param {string} toLangTag The lang tag of the conversion result.
* @returns The HTML page converter.
*/
export function HTMLConverter(converter, rootNode, fromLangTag, toLangTag) {
/**
* Perform the conversion on the page.
*/
function convert() {
function inner(currentNode, langMatched) {
/* class list 包含 ignore-opencc 的元素會跳過後續的轉換 */
if (currentNode.nodeType === Node.ELEMENT_NODE && currentNode.classList.contains('ignore-opencc')) return;
if (currentNode.lang === fromLangTag) {
langMatched = true;
currentNode.shouldChangeLang = true; // 記住 lang 屬性被修改了，以便恢復
currentNode.lang = toLangTag;
} else if (currentNode.lang && currentNode.lang.length) {
langMatched = false;
}
if (langMatched) {
/* Do not convert these elements */
if (currentNode.tagName === 'SCRIPT') return;
if (currentNode.tagName === 'STYLE') return;
/* 處理特殊屬性 */
if (currentNode.tagName === 'META' && currentNode.name === 'description') {
if (currentNode.originalContent == null) {
currentNode.originalContent = currentNode.content;
}
currentNode.content = converter(currentNode.originalContent);
} else if (currentNode.tagName === 'META' && currentNode.name === 'keywords') {
if (currentNode.originalContent == null) {
currentNode.originalContent = currentNode.content;
}
currentNode.content = converter(currentNode.originalContent);
} else if (currentNode.tagName === 'IMG') {
if (currentNode.originalAlt == null) {
currentNode.originalAlt = currentNode.alt;
}
currentNode.alt = converter(currentNode.originalAlt);
} else if (currentNode.tagName === 'INPUT' && currentNode.type === 'button') {
if (currentNode.originalValue == null) {
currentNode.originalValue = currentNode.value;
}
currentNode.value = converter(currentNode.originalValue);
}
}
for (const node of currentNode.childNodes) {
if (node.nodeType === Node.TEXT_NODE && langMatched) {
if (node.originalString == null) {
node.originalString = node.nodeValue; // 存儲原始字串，以便恢復
}
node.nodeValue = converter(node.originalString);
} else {
inner(node, langMatched);
}
}
}
inner(rootNode, false);
}
/**
* Restore the page to the state before the conversion.
*/
function restore() {
function inner(currentNode) {
/* class list 包含 ignore-opencc 的元素會跳過後續的轉換 */
if (currentNode.nodeType === Node.ELEMENT_NODE && currentNode.classList.contains('ignore-opencc')) return;
if (currentNode.shouldChangeLang) {
currentNode.lang = fromLangTag;
}
if (currentNode.originalString !== undefined) {
currentNode.nodeValue = currentNode.originalString;
}
/* 處理特殊屬性 */
if (currentNode.tagName === 'META' && currentNode.name === 'description') {
if (currentNode.originalContent !== undefined) {
currentNode.content = currentNode.originalContent;
}
} else if (currentNode.tagName === 'META' && currentNode.name === 'keywords') {
if (currentNode.originalContent !== undefined) {
currentNode.content = currentNode.originalContent;
}
} else if (currentNode.tagName === 'IMG') {
if (currentNode.originalAlt !== undefined) {
currentNode.alt = currentNode.originalAlt;
}
} else if (currentNode.tagName === 'INPUT' && currentNode.type === 'button') {
if (currentNode.originalValue !== undefined) {
currentNode.value = currentNode.originalValue;
}
}
for (const node of currentNode.childNodes) {
inner(node);
}
}
inner(rootNode);
}
return { convert, restore };
}