vertical-collection

Infinite Scroll and Occlusion at > 60FPS

vertical-collection is an ember-addon that is part of the smoke-and-mirrors framework. It focuses on improving initial and re-render performance in high-stress situations by providing a component for performant lists and svelte renders to match a core belief: Don't render the universe, render the scene.

TL;DR svelte render: the fewer things you need to render, the faster your renders will be.

Your web page is a universe, your viewport is the scene. Much like you wouldn't expect a video game to render out-of-scene content, your application should smartly cull the content it doesn't need to care about. Trimming excess content lets the browser perform both initial renders and re-renders at far higher frame-rates, as the only content it needs to focus on for layout is the content the user can see.

vertical-collection augments your existing app, it doesn't ask you to rewrite layouts or logic in order to use it. It will try its best to allow you to keep the conventions, structures, and layouts you want.

Install

ember install @html-next/vertical-collection

Usage

<VerticalCollection
    @items={{items}}
    @tagName="ul"
    @estimateHeight={{50}}
    @staticHeight={{false}}
    @bufferSize={{1}}
    @renderAll={{false}}
    @renderFromLast={{false}}
    @idForFirstItem={{idForFirstItem}}
    @firstReached={{firstReachedCallback}}
    @lastReached={{lastReachedCallback}}
    @firstVisibleChanged={{firstVisibleChangedCallback}}
    @lastVisibleChanged={{lastVisibleChangedCallback}}
     as |item i|>
    <li>
      {{item.number}} {{i}}
    </li>
</VerticalCollection>

Actions

firstReached - Triggered when scroll reaches the first element in the collection

lastReached- Triggered when scroll reaches the last element in the collection

firstVisibleChanged - Triggered when the first element in the viewport changes

lastVisibleChanged - Triggered when the last element in the viewport changes

Support Matrix

`vertical-collection` version	Supported Ember versions	Supported Node versions
`^v1.x.x`	`v1.12.0 - v3.8.x`	`?`
`^v2.x.x`	`v2.8.0 - v3.26.x`	`v12 - ?`
`^v3.x.x`	`v2.18.0+`	`v14+`
`^v4.x.x`	`v3.12.0+`	`v14+`

Support, Questions, Collaboration

Join the Ember community on Discord

Features

Infinite Scroll (bi-directional)

Infinite scroll that remains performant even for very long lists is easily achievable with the vertical-collection. It works via a scrollable div or scrollable body.