Use an anchor tags href value as the scrollTo target

scrollToAnchor.js

// Smooth scrolling to anchors
//
// This is a slightly modified version of the script provided by CSS Tricks
// https://css-tricks.com/snippets/jquery/smooth-scrolling/

(function ($) {
  // Select all links with hashes
  $('a[href*="#"]')
    // Remove links that don't actually link to anything
    .not('[href="#"]')
    .not('[href="#0"]')
    .click(function (event) {
      // On-page links
      if (
        location.pathname.replace(/^\//, '') == this.pathname.replace(/^\//, '')
        &&
        location.hostname == this.hostname
      ) {
        // Figure out element to scroll to
        let target = $(this.hash);
        target = target.length ? target : $('[name=' + this.hash.slice(1) + ']');
        // Does a scroll target exist?
        if (target.length) {
          // Only prevent default if animation is actually gonna happen
          event.preventDefault();
          $('html, body').animate({
            // Subtract 40 (the height of our sticky header)
            scrollTop: target.offset().top
          }, 1000);
        }
      }
    });
}(jQuery));

Gist updated so that the functionality no longer relies on a jQuery plugin.