Hot Module Replacement
Hot Module Replacement (HMR) is a development feature that allows modules to be updated in a running application without requiring a full page reload. It works by replacing modules in the browser's memory while preserving the application state, such as user input or component data. This enables developers to see code changes reflected immediately during development, significantly speeding up the feedback loop.
Developers should use HMR when building modern web applications with tools like Webpack, Vite, or Parcel to enhance productivity by eliminating manual refreshes and maintaining state across updates. It is particularly valuable in complex applications where reloading would reset user interactions, such as forms, games, or real-time dashboards, allowing for rapid iteration and debugging without disrupting the workflow.