Deep Dive: Array Internals & Memory Layout

Understanding JavaScript Arrays: A Deep Dive

JavaScript arrays are fundamental data structures that provide efficient ways to store and manipulate collections of items. However, understanding how they work under the hood is crucial for optimizing performance in your applications.

Key Concepts

1. Contiguous Memory Layout:

   • In JavaScript, arrays are stored as contiguous blocks of memory.
   • Each element's address can be calculated using a simple formula: baseAddress + index * elementSize.
   • This allows for constant-time access to any element via its index.

2. Dynamic Resizing:

   • Arrays automatically resize when elements are added beyond the current capacity.
   • When an array needs more space, it typically doubles in size and copies all existing elements to the new location.
   • This resizing operation is O(n), but since it happens infrequently (after n insertions), the average cost per insertion is amortized O(1).

3. Performance Characteristics:

   • Random Access: Arrays support constant-time access to any element via its index, making them ideal for scenarios where you need quick lookups.
   • Sequential Iteration: Due to cache locality, iterating through an array is very efficient because elements are stored cont

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