Proyectos de Subversion Moodle

// This file is part of Moodle - http://moodle.org/ //

// Moodle 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.

//

// Moodle 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 Moodle.  If not, see <http://www.gnu.org/licenses/>.

/**

 * Mathjax JS Loader.

 *

 * @module filter_mathjaxloader/loader

 * @copyright 2014 Damyon Wiese  <damyon@moodle.com>

 * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later

 */

import {

    eventTypes,

    notifyFilterContentRenderingComplete,

} from 'core_filters/events';

/**

 * URL to MathJax.

 * @type {string|null}

 */

let mathJaxUrl = null;

/**

 * Promise that is resolved when MathJax was loaded.

 * @type {Promise|null}

 */

let mathJaxLoaded = null;

/**

 * Called by the filter when it is active on any page.

 * This does not load MathJAX yet - it adds the configuration in case it gets loaded later.

 * It also subscribes to the filter-content-updated event so MathJax can respond to content loaded by Ajax.

 *

 * @param {Object} params List of configuration params containing mathjaxurl, mathjaxconfig (text) and lang

 */

export const configure = (params) => {

    let config = {};

    try {

        if (params.mathjaxconfig !== '') {

            config = JSON.parse(params.mathjaxconfig);

        }

    }

    catch (e) {

        window.console.error('Invalid JSON in mathjaxconfig.', e);

    }

    if (typeof config != 'object') {

        config = {};

    }

    if (typeof config.loader !== 'object') {

        config.loader = {};

    }

    if (!Array.isArray(config.loader.load)) {

        config.loader.load = [];

    }

    if (typeof config.startup !== 'object') {

        config.startup = {};

    }

    // Always ensure that ui/safe is in the list. Otherwise, there is a risk of XSS.

    // https://docs.mathjax.org/en/v3.2-latest/options/safe.html.

    if (!config.loader.load.includes('ui/safe')) {

        config.loader.load.push('ui/safe');

    }

    // This filter controls what elements to typeset.

    config.startup.typeset = false;

    // Let's still set the locale even if the localization is not yet ported to version 3.2.2

    // https://docs.mathjax.org/en/v3.2-latest/upgrading/v2.html#not-yet-ported-to-version-3.

    config.locale = params.lang;

    mathJaxUrl = params.mathjaxurl;

    window.MathJax = config;

    // Listen for events triggered when new text is added to a page that needs

    // processing by a filter.

    document.addEventListener(eventTypes.filterContentUpdated, contentUpdated);

};

/**

 * Add the node to the typeset queue.

 *

 * @param {HTMLElement} node The Node to be processed by MathJax

 * @private

 */

const typesetNode = (node) => {

    if (!(node instanceof HTMLElement)) {

        // We may have been passed a #text node.

        // These cannot be formatted.

        return;

    }

    loadMathJax().then(() => {

        // Chain the calls to typesetPromise as it is recommended.

        // https://docs.mathjax.org/en/v3.2-latest/web/typeset.html#handling-asynchronous-typesetting.

        window.MathJax.startup.promise = window.MathJax.startup.promise

            .then(() => window.MathJax.typesetPromise([node]))

            .then(() => {

                notifyFilterContentRenderingComplete([node]);

            })

            .catch(e => {

                window.console.log(e);

            });

    });

};

/**

 * Called by the filter when an equation is found while rendering the page.

 */

export const typeset = () => {

    const elements = document.getElementsByClassName('filter_mathjaxloader_equation');

    for (const element of elements) {

        typesetNode(element);

    }

};

/**

 * Handle content updated events - typeset the new content.

 *

 * @param {CustomEvent} event - Custom event with "nodes" indicating the root of the updated nodes.

 */

export const contentUpdated = (event) => {

    let listOfElementContainMathJax = [];

    let hasMathJax = false;

    // The list of HTMLElements in an Array.

    event.detail.nodes.forEach((node) => {

        if (!(node instanceof HTMLElement)) {

            // We may have been passed a #text node.

            return;

        }

        const mathjaxElements = node.querySelectorAll('.filter_mathjaxloader_equation');

        if (mathjaxElements.length > 0) {

            hasMathJax = true;

        }

        listOfElementContainMathJax.push(mathjaxElements);

    });

    if (!hasMathJax) {

        return;

    }

    listOfElementContainMathJax.forEach((mathjaxElements) => {

        mathjaxElements.forEach((node) => typesetNode(node));

    });

};

/**

 * Load the MathJax script.

 *

 * @return Promise that is resolved when MathJax was loaded.

 */

export const loadMathJax = () => {

    if (!mathJaxLoaded) {

        if (!mathJaxUrl) {

            return Promise.reject(new Error('URL to MathJax not set.'));

        }

        mathJaxLoaded = new Promise((resolve, reject) => {

            const script = document.createElement('script');

            script.type = 'text/javascript';

            script.onload = resolve;

            script.onerror = reject;

            script.src = mathJaxUrl;

            document.getElementsByTagName('head')[0].appendChild(script);

        });

    }

    return mathJaxLoaded;

};