Extracting Page Header and Footer

That is a great question. I like your idea of considering it separate artifacts.

On one side, you might need the data contained in the page-specific footer, for example if you need the page number when it doesn't correspond to the PDF page, or it may contain the current chapter, etc. On the other hand, most headers or footers contain the same information again and again, but it doesn't appear anywhere else, like for example, the name of the product the specsheet you're parsing, which is essential.

Perhaps it could still retain flexibility and cater to both cases by having options, like:

{headers:true, footers:true, inline: false, firstOnly: true}

So if you can have only headers or only footers, and you can choose whether to have them inline, so that a paragraph that spans two pages will be interrupted by a footer and then a header element. If you set inline to false it will put all the header and footer elements at the end. Whether it's just the first header or footer it encounters or all of them depend on the firstOnly option.