Garbage Collection

Summary

JavaScript's automatic process of freeing memory no longer reachable by any reference, so you don't have to manually deallocate memory like in C. Garbage collection is based on reachability rather than whether a variable 'looks unused', so lingering references can keep large object graphs alive.

• 1Read about the 'mark-and-sweep' algorithm most engines use. Then apply the idea in a small example so the theory becomes practical.
• 2Understand what 'reachability' means in the context of garbage collection. Be able to explain the concept in your own words and identify where it appears in a real application.
• 3Learn common patterns (forgotten timers, global references) that prevent objects from being collected.