Export to PDF with markdown crashes on empty lines

[nbelyh]

Are you requesting a feature, reporting a bug or asking a question?

reporting a bug

What is the current behavior?

PDF export crashes on empty lines (when using markdown)

What is the expected behavior?

PDF export does not crash, but produces empty lines when asked to

How would you reproduce the current behavior (if this is a bug)?

I am using surveyjs with markdown to render labels, and export to PDF.

When on the website, all works fine; however when exporting to PDF, empty line crashes the export:

Full example to reproduce on codepen: https://codepen.io/nbelyh/pen/poYdLpy

The crash happens if the "title" contains <br><br> sequence (empty line)

The crash is happening on this line: https://github.com/surveyjs/survey-pdf/blob/0aa70b911fd996bf78c2bed1be84b70d5e81662c/src/jspdf_plugins/from_html.js#L1082

I get this error:

Full source code (modified "getting started" example, added the markdown function). Same as above on codepen.

const json = {
  "pages": [{
    "elements": [{
      "type": "comment",
      "name": "suggestions",
      "title": "What would make <br><br>you more **satisfied** with our product?"
    }]
  }],
  "showQuestionNumbers": false
};

  function processMarkdown(survey, options) {
    //convert the markdown text to html
    let str = options.text;
    str = str.replace(/^(\d+)\./, '$1');
    str = str.replace(/^(\d+)\)/, '$1');
    str = marked.marked(str);
    // remove root paragraphs <p></p>
    str = str.substring(3);
    str = str.substring(0, str.length - 5);
    // set html
    options.html = str;
  }

function createSurveyPdfModel(surveyModel) {

    let pdfWidth = !!surveyModel && surveyModel.pdfWidth ? surveyModel.pdfWidth : 210;
    let pdfHeight = !!surveyModel && surveyModel.pdfHeight ? surveyModel.pdfHeight : 297;
    let options = {
        fontSize: 14,
        margins: {
            left: 10,
            right: 10,
            top: 10,
            bot: 10
        },

        format: [pdfWidth, pdfHeight]
    };
    const surveyPDF = new SurveyPDF.SurveyPDF(json, options);
    surveyPDF.onTextMarkdown.add(processMarkdown);
    if (surveyModel) {
        surveyPDF.data = surveyModel.data;
    }

    return surveyPDF;
}
function saveSurveyToPdf(filename, surveyModel) {
    createSurveyPdfModel(surveyModel).save(filename);
}

function SurveyPdfComponent() {

    const survey = new Survey.Model(json);
    survey.addNavigationItem({
        id: "survey_save_as_file", title: "Save as PDF", action: () => { saveSurveyToPdf("surveyResult.pdf", survey); }
    });
    survey.onTextMarkdown.add(processMarkdown);
    survey.data = {};
    return (<SurveyReact.Survey model={survey} />);
}

const root = ReactDOM.createRoot(document.getElementById("surveyElement"));
root.render(<SurveyPdfComponent />);

Specify your

• browser: Chrome
• browser version: latest as of writing
• surveyjs platform (angular or react or jquery or knockout or vue): react
• surveyjs version: 1.9.127

[nbelyh]

Ups. Have not seen that this is a duplicate. Closing as a duplicate of: https://github.com/surveyjs/survey-pdf/issues/287