The caches native npm modules leave behind: headers, binaries and Corepack

Most npm packages are JavaScript. A few are compiled, such as image processors, database drivers and file watchers, and those either download a prebuilt binary or compile against Node's headers. Both leave a cache behind, and none of them is the npm cache.

Why they pile up

• node-gyp keeps a header folder for every Node version you have compiled against. Switching versions with a version manager adds one each time.
• Packages that bundle a tool, such as ffmpeg-static, sharp or puppeteer, download it once per version into a cache named after the package.
• Corepack downloads every Yarn and pnpm version any project asks for.

Find and clear them

ls ~/Library/Caches | grep -iE 'node|gyp|ffmpeg|sharp|electron|prebuild'
du -sh ~/Library/Caches/node-gyp/* ~/.cache/node/* 2>/dev/null

# All safe to remove; they are downloads
rm -rf ~/Library/Caches/node-gyp ~/Library/Caches/ffmpeg-static-nodejs

The next npm install of a native module fetches only what the current Node needs. Larger downloads of the same kind are the Electron and Playwright caches, in the Electron cache and Playwright browsers. The main npm cache is in npm cache taking up space.