Arrays are objects in JavaScript

Arrays in JavaScript are objects with special behaviors, including a length property and the ability to have holes. Array methods are on Array.prototype. This object-like nature impacts performance and explains array-like objects. Understanding arrays as objects clarifies their flexibility in adding properties and manipulating lengths. JavaScript engines optimize common array patterns, but some actions can trigger slower modes. For optimal performance, set array sizes upfront, avoid holes, use consistent types, and don't add non-indexed properties.