Offset top document.querySelector - Javascript

Question

I use the following code to use smooth scroll when clicking a link with anchor. This works perfect but I need to add some offset top of 88 pixels, because of a static header.

How can I extend this code and add a off set top of 88px?

Code:

<script type="text/javascript" >
document.querySelectorAll('a[href^="#"]').forEach(anchor => {
    anchor.addEventListener('click', function (e) {
        e.preventDefault();

        document.querySelector(this.getAttribute('href')).scrollIntoView({
            behavior: 'smooth'
        });
    });
});
</script>