What is packager?

If you've built a desktop app using Electron and want to share it with users, you need a way to turn your code into something that actually runs on a computer. That's what this tool does. It takes your app's source code and bundles it with the Electron framework to produce ready-to-use files like a .app on Mac, a .exe on Windows, or a comparable package on Linux. You can run it from the command line or use it as a library in a JavaScript script. The tool handles the plumbing of finding or downloading the correct version of Electron for your target operating system, then combining it with your code into a folder ready for distribution. You point it at your source directory, tell it which platform and architecture you want to build for, and it produces the appropriate app bundle. If you don't specify a platform, it defaults to whatever machine you're running it on. This is aimed at developers who have already built an Electron app and need to get it into users' hands. For example, if you've built a note-taking app and want to ship a Mac version, you'd run a single command and get a .app file someone can double-click to open. You can also build for multiple platforms at once with a single flag. One thing worth noting: this tool produces the raw app bundles, not polished installers. If you want to create a Windows MSI installer, a Mac DMG, or a Linux DEB package, you'd pair it with a separate tool that takes the output from here and wraps it into the final distributable format. The README also flags that packaged Electron apps tend to be relatively large, since each bundle includes the full Electron runtime. There's also a platform constraint: Mac apps can only be properly signed if you're building on a Mac.