119 lines
3.8 KiB
JavaScript
119 lines
3.8 KiB
JavaScript
/*
|
|
* Copyright (C) 2021 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/>.
|
|
*/
|
|
|
|
/**
|
|
* This class is used to apply CSS styles to elements using a consistent method
|
|
* that is the same across different browsers.
|
|
*/
|
|
class CssStyleApplier {
|
|
/**
|
|
* Creates a new instance of the class.
|
|
* @param styleDataUrl The local URL to the JSON file continaing the style rules.
|
|
* The style rules should be of the format:
|
|
* [
|
|
* {
|
|
* selectors: [(selector:string)...],
|
|
* styles: [
|
|
* [(property:string), (value:string)]...
|
|
* ]
|
|
* }...
|
|
* ]
|
|
*/
|
|
constructor(styleDataUrl) {
|
|
this._styleDataUrl = styleDataUrl;
|
|
this._styleData = [];
|
|
this._cachedRules = new Map();
|
|
}
|
|
|
|
/**
|
|
* Loads the data file for use.
|
|
*/
|
|
async prepare() {
|
|
this._styleData = await this._fetchJsonAsset(this._styleDataUrl);
|
|
}
|
|
|
|
/**
|
|
* Applies CSS styles directly to the "style" attribute using the "class" attribute.
|
|
* This only works for elements with a single class.
|
|
* @param elements An iterable collection of HTMLElement objects.
|
|
*/
|
|
applyClassStyles(elements) {
|
|
const elementStyles = [];
|
|
for (const element of elements) {
|
|
const {className} = element;
|
|
if (className.length === 0) { continue; }
|
|
let cssTextNew = '';
|
|
for (const {selectorText, styles} of this._getRulesForClass(className)) {
|
|
if (!element.matches(selectorText)) { continue; }
|
|
cssTextNew += this._getCssText(styles);
|
|
}
|
|
cssTextNew += element.style.cssText;
|
|
elementStyles.push({element, style: cssTextNew});
|
|
}
|
|
for (const {element, style} of elementStyles) {
|
|
element.removeAttribute('class');
|
|
if (style.length > 0) {
|
|
element.setAttribute('style', style);
|
|
} else {
|
|
element.removeAttribute('style');
|
|
}
|
|
}
|
|
}
|
|
|
|
// Private
|
|
|
|
async _fetchJsonAsset(url) {
|
|
const response = await fetch(url, {
|
|
method: 'GET',
|
|
mode: 'no-cors',
|
|
cache: 'default',
|
|
credentials: 'omit',
|
|
redirect: 'follow',
|
|
referrerPolicy: 'no-referrer'
|
|
});
|
|
if (!response.ok) {
|
|
throw new Error(`Failed to fetch ${url}: ${response.status}`);
|
|
}
|
|
return await response.json();
|
|
}
|
|
|
|
_getRulesForClass(className) {
|
|
let rules = this._cachedRules.get(className);
|
|
if (typeof rules !== 'undefined') { return rules; }
|
|
|
|
rules = [];
|
|
this._cachedRules.set(className, rules);
|
|
|
|
const classNamePattern = new RegExp(`.${className}(?![0-9a-zA-Z-])`, '');
|
|
for (const {selectors, styles} of this._styleData) {
|
|
const selectorText = selectors.join(',');
|
|
if (!classNamePattern.test(selectorText)) { continue; }
|
|
rules.push({selectorText, styles});
|
|
}
|
|
|
|
return rules;
|
|
}
|
|
|
|
_getCssText(styles) {
|
|
let cssText = '';
|
|
for (const [property, value] of styles) {
|
|
cssText += `${property}:${value};`;
|
|
}
|
|
return cssText;
|
|
}
|
|
}
|