Sticky Header

This library allows you to create sticky headers. It uses position: sticky and IntersectionObserver.

The plugin doesn't require jQuery, but it adds itself to jQuery if jQuery exists on the page.

Installing

Use npm (or yarn) to install the package.

``npm2yarn
npm install --save @smartimpact-it/sticky-header
`

Initializing in JavaScript

To initialize the library, you need to create a new instance of the StickyHeader class:

`javascript
import StickyHeader from '@smartimpact-it/sticky-header';

const header = document.querySelector('header.page-header');
new StickyHeader(header, options);
`

Or using jQuery:

`javascript
import '@smartimpact-it/sticky-header';

$('header.page-header).stickyHeader(options);
`

The options object can have the following properties:

- mainClass - the class added when the plugin is initialized (default: sticky)
- pinnedClass - the class added when the element becomes "stuck" (default: sticky-pinned)
- unpinnedClass - the class added when the element becomes "unstuck" (default: sticky-unpinned)
- offset - the offset (in pixels) where the element should become "stuck" (default: 0)
- addBodyClasses - add the pinnedClass and unpinnedClass classes to the body element as well (default: true)

Warnings

1. The plugin uses position: sticky. This is supported in all modern browsers. However, position: sticky has some requirements: you must not have parent elements with overflow: hidden, or otherwise it will not work (the position will be static). If you cannot get it to start, check that you don't have overflow: hidden on a parent element.

2. If you change the header size depending on the "stuck"/"unstuck" status, you will probably need to prevent the window from scrolling when this happens (the header will push the content).

If you have a #wrapper element around the content (including the header), you could do something like this:

`css
header.sticky {
top: 0;
position: sticky;
}

/ fix for when the header grows in size when it becomes unpinned and the scroll position changes (we need to scroll more) /
@supports (position: sticky) {
body.sticky-unpinned #wrapper {
overflow-anchor: none;
}
}
``