How to make Card Header Title bold in Gmail Add-on?

Question

How to make Card Header Title bold in Gmail Add-on? I tried this, but it doesn`t work:

function mainCardBuild(content) {
    return CardService.newCardBuilder()
        .setHeader(
            CardService.newCardHeader().setTitle('<b> MY TITLE </b>')) //doesn`t work bold
        .addSection(content)
        .build();
}

I`m sure that we have opportunity to do it, because in Slack Add-on I saw it. Bold card header in Slack

Answer 1

You cannot insert HTML in your title, but you can insert basic HTML into Text Paragraphs (see: Informational widgets and supported text formatting). Your code could then look as follows:

function mainCardBuild(content) {
    var boldHeaderSection = CardService.newCardSection()
      .addWidget(CardService.newTextParagraph().setText('<b>MY TITLE</b>'));
    return CardService.newCardBuilder()
        .addSection(boldHeaderSection)
        .addSection(content)
        .build();
}

In case you need to do more customisations, I suggest you check out the following example, which uses HTML to create the view Translate Add-on Quickstart.