The phrase signifies a common workflow in web development, particularly when using tools that support hot module replacement or live reloading. It describes the action of modifying the `app.js` file, typically the main JavaScript file in a project’s source directory, and then saving those changes. The subsequent “reload” refers to the automatic refresh of the web application in the browser, reflecting the modifications made to the code.
This process greatly accelerates development. Instead of manually refreshing the browser after each change, the system automatically updates the application. This instantaneous feedback loop allows developers to quickly iterate on their code, test new features, and fix bugs more efficiently. Historically, developers had to rely on manual browser refreshes, slowing down the development lifecycle. The advent of live reloading tools has transformed the development experience, allowing for a more fluid and productive workflow.