Optimization: Avoid an excessive DOM size

[rfultz]

Background

Looking to optimize the site's performance and that of the homepage specifically, the Lighthouse tool in Chromium browsers has made some suggestions. Some of these will have repercussions throughout the app so we're going to make them their own tickets.

Recommendation: Avoid an excessive DOM size

A large DOM will increase memory usage, cause longer style calculations, and produce costly layout reflows. details

Overview

We could change our document structure/appearance to speed initial page draw

Benefit (the 80 of 80/20)

Minimal? Lighthouse flagged it because we have 1,534 elements, but they flag anything over 1,500.

Effort (the 20 of 80/20)

Moderate to Significant

Complications

• With remediations like hiding DOM elements or removing them until needed, we could hurt accessibility

Related tickets

• Preload key requests
• Remove unused JavaScript
• Remove unused CSS
• Preconnect to required origins
• Eliminate render-blocking resources
• Ensure text remains visible during webfont load
• Reduce the impact of third-party code
• Does not use passive listeners to improve scrolling performance
• Image elements do not have explicit width and height
• Serve static assets with an efficient cache policy
• Minimize main-thread work
• Reduce JavaScript execution time
• Avoid enormous network payloads
• [aria-hidden="true"] elements contain focusable descendents
• Elements with an ARIA [role] that require children to contain a specific [role] are missing some or all of those required children
• [aria-*] attributes do not have valid values
• ARIA IDs are not unique
• Lists do not contain only
• elements and script supporting elements (<script> and )
• [user-scalable="no"] is used in the element or the [maximum-scale] attribute is less than 5
• Links to cross-origin destinations are unsafe
• Serves images with low resolution