style ‘blockquote’ not recognized

My mammoth-options.js file is:

function MAMMOTH_OPTIONS(mammoth) {
    var styleMap = [
        "p[style-name='blockquote'] => blockquote > p:fresh",
    ];

    function setParagraphStyleNameFromFonts(fonts, styleName, skipStyleNameRegex) {
        return mammoth.transforms.paragraph(function(paragraph) {
            var runs = mammoth.transforms.getDescendantsOfType(paragraph, "run");
            var isMatch = runs.length > 0 && runs.every(function(run) {
                return run.font && fonts.indexOf(run.font.toLowerCase()) !== -1;
            });
            if (isMatch && !skipStyleNameRegex.test(paragraph.styleName)) {
                return {...paragraph, styleName: styleName};
            } else {
                return paragraph;
            }
        });
    }

    return {
        styleMap: styleMap,
        // If a paragraph is entirely made up of runs that use monospace fonts,
        // update the paragraph to use the style "Code Block" if it doesn't
        // already have a "Code Block" style.
        transformDocument: setParagraphStyleNameFromFonts(
            ["consolas", "courier", "courier new"],
            "Code Block",
            /^Code Block/i
        )
    };
}

I’ve created a docx file containing a paragraph with the style ‘blockquote’, however in the resulting wordpress post the paragraph is is not surrounded by blockquote tags. Where do I begin to look for the problem?