README.md

Swup Morph Plugin

A swup plugin for morphing dom nodes into the new page.

Allows morphing containers into the new page without replacing or animating them. The prime use cases are headers and menus on multi-language sites: you might not want to swap these elements out with a transition on each page visit, however you'd still want to update any URLs, labels or classnames when the user switches between languages.

Behind the scenes, it uses morphdom to update the existing DOM nodes to match the same DOM nodes on the new page being loaded. This will leave any event handlers in place, as opposed to setting innerHTML on the target.

Installation

Install the plugin from npm and import it into your bundle.

npm install swup-morph-plugin

import SwupMorphPlugin from 'swup-morph-plugin';

Or include the minified production file from a CDN:

<script src="https://unpkg.com/swup-morph-plugin@1"></script>

Usage

To run this plugin, include an instance in the swup options.

const swup = new Swup({
  plugins: [new SwupMorphPlugin()]
});

Morphed containers

The plugin provides two ways of choosing the containers to be morphed:

Container option

Pass in a list of selectors into the plugin options to let it know about morphable containers. Use this method if you have a limited and predictable number of containers to morph.

new SwupMorphPlugin({
  containers: ['#nav']
})

<nav id="nav">
  <!-- Morphed by this plugin -->
</nav>
<main id="swup">
  <!-- Replaced normally by swup -->
</main>

Data attribute

Add a data-swup-morph attribute with a unique identifier on containers to be morphed. The plugin will find all containers with this attribute and match the outgoing and incoming versions of each container by the value of the attribute. Use this method if you have lots of dynamically created morphable containers.

<nav data-swup-morph="nav">
  <!-- Morphed by this plugin -->
</nav>
<main id="swup">
  <!-- Replaced normally by swup -->
</main>

Options

containers

Array of specific DOM selectors that will be morphed into the new page.

{
  containers: ['#nav']
}

updateCallbacks

Callbacks to run before elements are updated. This can be used to persist or discard certain attributes. If the callback returns false, the element will not be updated.

See the morphdom docs on the onBeforeElUpdated option for details.

{
  containers: ['#widget'],
  updateCallbacks: [
    (fromEl, toEl) => {
      // Persist ARIA attributes on buttons and inputs
      if (fromEl.hasAttribute('aria-pressed')) {
        toEl.setAttribute('aria-pressed', fromEl.getAttribute('aria-pressed'))
      }
    }
  ]
}