데브허브 | DEVHUB | Advent of Svelte 2025 - Day 19: stream upload #javascript #sveltejs #webdevelopment
When uploading large files through forms, SvelteKit previously had to unpack the entire file on the server just to validate other form fields like a missing name input. The latest SvelteKit introduces a custom protocol that reorders form data, moving file content after the headers. This allows the server to validate text fields immediately without waiting to process gigabytes of data first. The browser still takes the same time to send the file, but validation errors now return almost instantly. Best of all, you get this performance improvement automatically just by updating to the latest SvelteKit version.