Tree shaking is a technique used in module bundling, which involves removing unused or unnecessary code from the final bundle. This helps to reduce the overall size of the bundle, making it faster to load and use, as well as potentially reducing licensing costs.

Tree shaking works by analyzing the dependencies between modules and identifying any modules that are not used in the application. It then removes those modules from the final bundle. This process can be automated using various tools or manual inspection of the codebase.

Tree shaking is especially useful when working with large or complex applications that have many dependencies, as it helps to reduce the amount of code that needs to be loaded and executed at runtime. It can also help to improve performance by reducing the overall size of the bundle, which allows it to be loaded more quickly.