Array Flatten in JavaScript

Flattening arrays is one of those concepts that shows up everywhere—from real-world coding tasks to technical interviews. In JavaScript, flattening an array refers to converting a nested (multi-dimensional) array into a single-level array by extracting all sub-elements. What nested arrays are Nested arrays, also known as multi-dimensional arrays, are arrays that contain other arrays as elements. They represent hierarchical data, such as a grid, tree-like structures, or complex API responses. Exa