Garbage Collection In Javascript

At its core, garbage collection is an automatic memory management process. It's responsible for identifying and reclaiming memory that is no longer needed by our program. This helps prevent memory leaks, which can lead to performance degradation and even application crashes.

Understanding garbage collection is essential for writing efficient and robust JavaScript code. By knowing how it works, we can:

• - Avoid memory leaks that can impact application performance.
• - Optimize memory usage to create faster and more responsive applications.
• - Focus on solving problems and building features without getting bogged down by manual memory management.

Some common garbage collection algorithms which are used are as follows :-

• Reference Counting: This algorithm keeps track of the number of references to each object. When the reference count drops to zero, the object is no longer needed and can be safely deallocated. This approach can quickly identify objects that are no longer in use but has issues with circular references, where objects reference each other, leading to memory leaks.
• Mark and Sweep: This algorithm involves two phases. In the "mark" phase, the garbage collector identifies all objects that are reachable from a root set (e.g., global variables). In the "sweep" phase, it traverses the entire memory, reclaiming memory that is not marked as reachable. Mark-and-sweep handles circular references but can lead to fragmentation.
• Generational Garbage Collection: This algorithm is based on the observation that most objects die young. It divides memory into generations, with new objects allocated in the "young" generation. The garbage collector frequently collects the young generation, promoting long-lived objects to the "old" generation. This approach takes advantage of the generational hypothesis to improve efficiency.
• Incremental and Concurrent Garbage Collection: These algorithms aim to reduce the impact of garbage collection on the application's performance. Incremental garbage collection breaks the collection process into smaller steps, interleaving them with the application's execution. Concurrent garbage collection runs in parallel with the application, reducing the time spent on garbage collection.
• Copying Garbage Collection: This algorithm divides memory into two equal halves, the "from" space and the "to" space. Objects are initially allocated in the "from" space. When garbage collection is triggered, the live objects are copied to the "to" space, and the roles of the spaces are swapped. This approach eliminates fragmentation but requires additional memory.
• Tricolor Mark and Sweep: An extension of the traditional mark-and-sweep algorithm that uses three colors to mark objects as white (unvisited), gray (reachable but not explored), and black (reachable and explored). This approach allows the garbage collector to handle objects that are being modified during the collection process.