Modernizing Legacy Vue 2: Why Webpack-to-Vite Migration Is More Complex Than It Seems

Most Vite migration guides assume modern projects with updated dependencies, but real-world legacy Vue 2 applications built on Webpack 2 face far greater complexity. The critical insight is that Webpack performs countless hidden tasks beyond bundling—alias resolution, polyfill injection, environment variable handling, asset processing—that must be explicitly replicated in Vite. Understanding and documenting these existing responsibilities before starting migration is essential for success in production systems.