Most web apps ship far more JavaScript than they need. The culprit is rarely your code — it's the dependencies. A single date formatting library can add 70KB gzipped. A chart library can add 200KB. Bundle analysis tools make these costs visible so you can make informed tradeoffs.

The Analysis Workflow

Run your bundler's analyze mode to generate a treemap visualization. Look for the largest rectangles — those are your biggest dependencies. Check if you're importing the entire library when you only use one function. Tools like bundlephobia.com show the cost of a package before you install it.