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Bundle size creep goes unnoticed until PR review — so I built `buildwatch`

#node #devtools #productivity #webdev

The problem

During development, bundle size creep goes unnoticed — there is no fast way to see that a code change just added 50 KB to your dist folder until it surfaces in a PR review or a production performance regression.

If you've hit this before, you know how it goes — you end up finding out during a PR review, or worse, after a production deploy.

As a solution, I created buildwatch

Watch your build output directory and report file size changes on every rebuild

It's zero-dependency Node.js, so you can run it immediately without installing anything:

npx buildwatch ./dist
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Output:

buildwatch v1.0.0
Watching /projects/myapp/dist
Initial state: 3 files, 1.0 MB total

[10:23:41] 2 files changed

  main.js          136.4 KB  +12.1 KB (+9.7%)
  main.css           8.3 KB  +0.1 KB (+1.2%)
  vendor.js        892.1 KB  no change

  Total: 1,036.8 KB  +12.2 KB (+1.2%)
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How it works

Pure Node.js using fs.watch() for directory monitoring and fs.stat() for file sizes, with 300ms debouncing to handle rapid build events, printing ANSI-colored per-file and total size deltas.

Why I built it

Found repeated complaints in r/webdev and r/node about not noticing bundle size regressions until PR review or production. Existing tools like bundlesize and size-limit require CI config changes or build plugin integration. No popular zero-dep tool gives you instant terminal feedback during local development — a file watcher that just runs alongside your dev server fills this gap cleanly.

Try it 

npx buildwatch --help
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Part of µ micro — one new developer tool, shipped every day. All tools are zero-dependency Node.js and run instantly with npx.

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