Manifest Web Performance: Balancing JavaScript, Rendering Techniques, and Hardware Considerations

Creating an interactive web interface often involves sending a large amount of JavaScript code to users, which affects performance.

It's important to balance the use of JavaScript to ensure fast loading while maintaining high quality user interactions.

There is a trend towards "zero JavaScript use", emphasizing reliance on default browser capabilities.

Various rendering models have emerged, such as server-side rendering (SSR), island architecture, and partial hydration.

SSR generates the full HTML code on the server, eliminating the need to send JavaScript to the client, but this can delay the interactivity of single-page applications.

Progressive hydration selectively loads and displays components to enhance performance.

Optimizing JavaScript bundles can increase loading speed, reduce memory usage, and lower CPU costs.

The runtime performance of JavaScript is critical, but the costs of syntactic parsing and compilation are less important.

It's important to consider hardware optimization, CPU performance, thermal regulation, cache size, and energy consumption constraints on various devices.

Network latency and bandwidth also affect website performance.

Understanding the real cost of JavaScript and optimizing for hardware and network conditions can significantly enhance website performance.

The cumulative effect of frameworks, libraries, UI components, third-party code, trackers, and analytics, known as the "JavaScript utility tax", can significantly impact performance.

The goal is to provide users with a fast, interactive interface as quickly as possible.

Strategies for enhancing web application performance include dynamic component imports, bundle splitting, route-based and component-based code splitting, and import-on-view.

Various approaches to rendering and hydration include island architecture, progressive hydration, renewable hydration, server components in React, server-side streaming rendering, and selective hydration.

I emphasized the importance of performance budgets and testing on real devices.

I recommend a free book on performance patterns available at patterns.dev.