<dom-flip>

🔀 Smooth position animation for web components.

Demo

This element is an implementation of the FLIP-technique for arbitrary elements. Simply place it around the elements you indend to reorder and they will smoothly slide over the screen when moved.

Installation

This element lives on npm. Install with yarn add dom-flip or npm install --save dom-flip.

Usage

You can use this element together with any element that modifies the DOM. The animated elements must be direct children of the dom-flip element.

To be able to correlate changes in the model to changes to the DOM, this element requires that you give every element a unique ID. This must be an attribute on the element itself and cannot be a property (because properties cannot be observed via MutationObserver).

Polymer's dom-repeat:

<dom-flip>
    <!--
        If you change the order of the elements inside items, the elements will
        smoothly glide to their new place.
    -->
    <dom-repeat items="[[items]]">
        <template>
            <my-item data-flip-id$="[[item.id]]">[[item.name]]</my-item>
        </template
    </dom-repeat>
</dom-flip>

lit-html:

const template = (items: { id: string, name: string }[]) => html`
    <dom-flip>
        ${items.map(item => html`<div data-flip-id="${item.id}">${item.name}</div>`)}
    </dom-flip>
`;

// Render some items
const result = template([
    { id: "1", name: "Hello" },
    { id: "2", name: ", " },
    { id: "3", name: "World!" }
]);
render(result, renderNode);

// ... next animation frame

// Change their order
const result = template([
    { id: "1", name: "Hello" },
    { id: "3", name: "World!" },
    { id: "2", name: ", " }
]);

// Positions are animated and the items will smoothly glide to their new place
render(result, renderNode);

iron-list

Although we wish it did, this element will not work with <iron-list> due to the virtualization. Maybe this can be fixed in the future.

Automatic registration

You can import the custom element class from dom-flip/element if you don't want it to automatically be registered within the custom elements registry.

Performance

The element is designed to avoid layout thrashing as much as possible by batching work into microtasks and to animation frame timing.

License

MIT