JavaScript's array methods are one of those topics where the basics are well-known but the full picture saves significant time. Here's a practical reference, from the commonly used to the ones most developers forget exist. The big three: map, filter, reduce map — transform each element map() creates a new array by applying a function to each element: const prices = [ 10 , 20 , 30 ]; const withTax = prices . map ( price => price * 1.2 ); // [12, 24, 36] const users = [{ name : ' Alice ' , age : 30 }, { name : ' Bob ' , age : 25 }]; const names = users . map ( user => user . name ); // ['Alice', 'Bob'] Enter fullscreen mode Exit fullscreen mode map() always returns an array of the same length. If you want to transform and potentially skip elements, use filter() + map() chained, or use reduce() . filter — select elements filter() creates a new array containing only elements where the function returns true : const numbers = [ 1 , 2 , 3 , 4 , 5 , 6 ]; const evens = numbers .…