node.js - Get text of previous header in HTML

Question

I have a HTML which looks like this:

<h1>Title</h1>
<p>Some additional content, can be multiple, various tags</p>
<h2><a id="123"></a>Foo</h2>
<p>Some additional content, can be multiple, various tags</p>
<h3><a id="456"></a>Bar</h3>

Now, for each anchor with id, I want to find out the header hierarchy, e.g. for the anchor with id="123" I would like to get something like [{level: 1, title: "Title"}, {level: 2, title: "Foo"}], similarly for anchor with id="456", I would like to get [{level: 1, title: "Title"}, {level: 2, title: "Foo"}, {level: 3, title: "Bar"}].

My code looks like this so far:

const linkModel: IDictionary<ILinkModelEntry> = {};
const $ = cheerio.load(html);
$("a").each((_i, elt) => {
    const anchor = $(elt);
    const id = anchor.attr().id;
    if (id) {
        const parent = anchor.parent();
        const parentTag = parent.prop("tagName");
        let headerHierarchy: any[] = [];
        if (["H1", "H2", "H3", "H4", "H5", "H6"].includes(parentTag)) {
            let level = parseInt(parentTag[1]);
            headerHierarchy = [{level, text: parent.text()}];
            level--;
            while (level > 0) {
                const prevHeader = parent.prev("h" + level);
                const text = prevHeader.text();
                headerHierarchy.unshift({level, text});
                level--;
            }
        }
        linkModel["#" + id] = {originalId: id, count: count++, headerHierarchy};
    }
});

What am I doing wrong, since

const prevHeader = parent.prev("h" + level);
const text = prevHeader.text();

always returns an empty string (i.e. "")?

Answer 1

等待大神答复