Using Mammoth style_map to apply inline styles and custom attributes

Question

I'd like to use Mammoth's style map to apply inline styles, like color:red and custom tags/attributes, though I cannot seem to find anything in the docs that suggest I can. Does mammoth have the capability to do inline styling?

Simple tags and classes works fine, e.g. p[style-name='Heading 3'] => div.foo:fresh

However I'd like to do something like this: p[style-name='Heading 3'] => div(color:red):fresh or p[style-name='Heading 3'] => div, cust_tag:val:fresh

Answer 1

I had the same trouble. The author of the library seems pretty uninterested in adding in-line styles as well. The trick is to just add a class using the mapping you're referring to, then later parse out that particular class and apply the in-line styles.

For example, here I've assigned classes to aligned text, 'left-aligned' and 'right-aligned'. Then from the MammothJS result, I run it through this function to get the class -> in-line style conversion.

function transformHTML(html) {
    const doc = new DOMParser().parseFromString(html, "text/html");
    doc.querySelectorAll("[class]").forEach((el) => {
        const classes = el.getAttribute("class").split(" ");
        const style = classes.reduce((acc, className) => {

        // Add additional cases to handle other classes as needed
        switch (className) {
            case "left-aligned":
                return acc + "text-align: left;";
            case "center-aligned":
                return acc + "text-align: center;";
            case "right-aligned":
                return acc + "text-align: right;";
            default:
                return acc;
        }

        }, "");
        el.removeAttribute("class");
        el.setAttribute("style", style);
    });
    return doc.documentElement.innerHTML;
}