@oat-sa/tao-item-runner-qti/src/qtiItem/core/Math.js

TAO QTI Item Runner modules

import $ from 'jquery';
import _ from 'lodash';
import Element from 'taoQtiItem/qtiItem/core/Element';
import rendererConfig from 'taoQtiItem/qtiItem/helper/rendererConfig';
import NamespacedElement from 'taoQtiItem/qtiItem/mixin/NamespacedElement';

var Math;

/**
 * Remove the closing MathML tags and remove useless line breaks before and after it
 *
 * @param {String} mathML
 * @param {String} nsName
 * @returns {String}
 */
function _stripMathTags(mathML, nsName) {
    var regex = new RegExp('<(/)?' + (nsName ? nsName + ':' : '') + 'math[^>]*>', 'g');
    return mathML
        .replace(regex, '')
        .replace(/^\s*[\r\n]/gm, '') //remove first blank line
        .replace(/\s*[\r\n]$/gm, ''); //last blank line
}

/**
 * Remove mathML ns name prefix from the mathML
 *
 * @param {String} mathML
 * @param {String} nsName
 * @returns {String}
 */
function _stripNamespace(mathML, nsName) {
    var regex = new RegExp('<(/)?' + (nsName ? nsName + ':' : ''), 'g');
    return mathML.replace(regex, '<$1');
}

/**
 * Check if the mathML string is to be considered empty
 *
 * @param {String} mathStr
 * @returns {Boolean}
 */
function _isEmptyMathML(mathStr) {
    var $math,
        mathText,
        hasContent = false;

    if (mathStr && mathStr.trim()) {
        $math = $($.parseHTML(mathStr));
        mathText = $math.text();
        hasContent = _.isString(mathText) && !!mathText.trim();
    }

    return !hasContent;
}

Math = Element.extend({
    qtiClass: 'math',
    defaultNsName: 'm',
    defaultNsUri: 'http://www.w3.org/1998/Math/MathML',
    nsUriFragment: 'MathML',
    init: function(serial, attributes) {
        this._super(serial, attributes);
        this.ns = null;
        this.mathML = '';
        this.annotations = {};
    },
    setAnnotation: function(encoding, value) {
        this.annotations[encoding] = _.unescape(value);
    },
    getAnnotation: function(encoding) {
        return this.annotations[encoding];
    },
    removeAnnotation: function(encoding) {
        delete this.annotations[encoding];
    },
    setMathML: function(mathML) {
        var ns = this.getNamespace(),
            nsName = ns.name && ns.uri ? ns.name : '';

        mathML = _stripMathTags(mathML, nsName);
        if (ns) {
            mathML = _stripNamespace(mathML, nsName);
        }
        this.mathML = mathML;
    },
    getMathML: function() {
        return this.mathML;
    },
    render: function() {
        var args = rendererConfig.getOptionsFromArguments(arguments),
            renderer = args.renderer || this.getRenderer(),
            tag = this.qtiClass,
            raw = this.mathML,
            body = raw,
            ns = this.getNamespace(),
            annotations = '',
            encoding,
            defaultData;

        for (encoding in this.annotations) {
            annotations +=
                '<annotation encoding="' + encoding + '">' + _.escape(this.annotations[encoding]) + '</annotation>';
        }

        if (annotations) {
            if (raw.indexOf('</semantics>') > 0) {
                raw = raw.replace('</semantics>', annotations + '</semantics>');
            } else {
                raw = '<semantics>' + raw + annotations + '</semantics>';
            }
        }

        if (ns && ns.name) {
            body = raw.replace(/<(\/)?([^!<])/g, '<$1' + ns.name + ':$2');
            tag = ns.name + ':' + tag;
        }

        body = body.replace(/<!--.*?-->/g, ''); // remove Mathjax-generated comments
        body = body.replace(/&lt;!--.*?--&gt;/g, ''); // fix for broken items because of Mathjax comments

        defaultData = {
            block: this.attr('display') === 'block' ? true : false,
            body: body,
            raw: raw,
            tag: tag,
            ns: ns
        };

        return this._super(_.merge(defaultData, args.data), args.placeholder, args.subclass, renderer);
    },
    isEmpty: function() {
        return _isEmptyMathML(this.mathML) && (!this.annotations.latex || !this.annotations.latex.trim());
    }
});

NamespacedElement.augment(Math);

export default Math;