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44. How Garbage collection in JavaScript works?

JavaScript has an automatic garbage collection feature that frees up memory occupied by objects that are no longer in use. The garbage collection process identifies objects that are no longer referenced by the program and then removes them from memory.

The garbage collector in Javascript works by tracking objects that are reachable. An object is considered reachable if it can be accessed through a chain of references from a root object. The root objects in JavaScript are the global objects, local objects, and function parameters.

During the garbage collection process, the collector runs through all the objects in the memory and identifies objects that are no longer reachable. These objects are marked for deletion, and their memory is reclaimed. The garbage collection process in JavaScript is non-deterministic, meaning it is not possible to predict exactly when the garbage collection process will run.

To optimize garbage collection, JavaScript engines employ various techniques such as generational collection, incremental collection, and idle-time collection. These techniques ensure that garbage collection occurs only when necessary and does not interfere with the performance of the program.

In summary, garbage collection in JavaScript works by identifying objects that are no longer reachable and removing them from memory to free up space for new objects.