One Pager Cheat Sheet

• The article discusses the importance of understanding how memory allocation and garbage collection in JavaScript work, as it's essential for building efficient applications, preventing memory leaks, and improving code performance.
• The JavaScript Memory Heap is a region of memory where JavaScript data structures such as objects, strings, and arrays are stored and is separate from the call stack; managing it efficiently is important to prevent slowdowns or crashes due to memory limits that vary between browsers and devices.
• Garbage collection is the automatic process of freeing up memory on the heap that is no longer accessible by an application, using various strategies like reference counting, mark and sweep, and generational collection to prevent memory leaks and optimize coding.
• The garbage collector in the JavaScript engine periodically frees up memory allocated to unreachable or 'dead' objects on the heap, thereby managing memory 'lives' without explicit handling by the programmer.
• In JavaScript, garbage collection operates principally via the mark-and-sweep and reference counting strategies, but notably does not employ the copying strategy due to potential memory inefficiency.
• To optimize memory usage in JavaScript, best practices include avoiding unwanted references by setting objects to null or undefined for garbage collection, minimizing objects in loops via reuse, and using object pooling to maintain a reserve of objects rather than allocating new memory; you should also limit strings to primitives and avoid memory leaks by careful handling of global variables, event listeners, closures and DOM references.
• The heap memory in JavaScript, used for dynamic memory allocation, is not unlimited but is limited by available system memory, JavaScript engine parameters, or memory management principles, and excessive memory allocation can cause an out of memory error; different JavaScript engines have varying heap memory limits, such as the 1.4GB limit in Node.js's V8 JavaScript Engine, which can lead to the need for careful memory management techniques, like avoiding memory leaks and using object pooling.
• This tutorial covers the core concepts of memory management in JavaScript, including the function of the heap, garbage collection, strategies such as reference counting and mark-and-sweep, and best practices for optimizing memory usage, with the goal of avoiding memory leaks, writing performant code and building robust applications.