yomichan/ext/js/dom/simple-dom-parser.js

131 lines
3.7 KiB
JavaScript
Raw Normal View History

/*
* Copyright (C) 2020-2022 Yomichan Authors
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <https://www.gnu.org/licenses/>.
*/
/* globals
* parse5
*/
class SimpleDOMParser {
constructor(content) {
this._document = parse5.parse(content);
this._patternHtmlWhitespace = /[\t\r\n\f ]+/g;
}
getElementById(id, root=null) {
for (const node of this._allNodes(root)) {
if (typeof node.tagName === 'string' && this.getAttribute(node, 'id') === id) {
return node;
}
}
return null;
}
getElementByTagName(tagName, root=null) {
for (const node of this._allNodes(root)) {
if (node.tagName === tagName) {
return node;
}
}
return null;
}
getElementsByTagName(tagName, root=null) {
const results = [];
for (const node of this._allNodes(root)) {
if (node.tagName === tagName) {
results.push(node);
}
}
return results;
}
getElementsByClassName(className, root=null) {
const results = [];
for (const node of this._allNodes(root)) {
if (typeof node.tagName === 'string') {
const nodeClassName = this.getAttribute(node, 'class');
if (nodeClassName !== null && this._hasToken(nodeClassName, className)) {
results.push(node);
}
}
}
return results;
}
getAttribute(element, attribute) {
for (const attr of element.attrs) {
if (
attr.name === attribute &&
typeof attr.namespace === 'undefined'
) {
return attr.value;
}
}
return null;
}
getTextContent(element) {
let source = '';
for (const node of this._allNodes(element)) {
if (node.nodeName === '#text') {
source += node.value;
}
}
return source;
}
static isSupported() {
return typeof parse5 !== 'undefined';
}
// Private
*_allNodes(root) {
if (root === null) {
root = this._document;
}
// Depth-first pre-order traversal
const nodeQueue = [root];
while (nodeQueue.length > 0) {
const node = nodeQueue.pop();
yield node;
const childNodes = node.childNodes;
if (typeof childNodes !== 'undefined') {
for (let i = childNodes.length - 1; i >= 0; --i) {
nodeQueue.push(childNodes[i]);
}
}
}
}
_hasToken(tokenListString, token) {
let start = 0;
const pattern = this._patternHtmlWhitespace;
pattern.lastIndex = 0;
while (true) {
const match = pattern.exec(tokenListString);
const end = match === null ? tokenListString.length : match.index;
if (end > start && tokenListString.substring(start, end) === token) { return true; }
if (match === null) { return false; }
start = end + match[0].length;
}
}
}