In JavaScript, what does the 'map()' function do?

The 'map()' function in JavaScript is specifically designed to create a new array by applying a specified function to each element of the original array. When you invoke the 'map()' method, it iterates over each element, performs the designated transformation defined in the callback function, and constructs a new array containing the results of these transformations.

For example, if you have an array of numbers and you want to double each number, you can use the 'map()' function to apply a doubling function to each element, resulting in a new array with the doubled values. It is important to note that 'map()' does not modify the original array; instead, it produces a new one, which emphasizes its functional programming nature.

The other options describe different array methods: filtering involves the 'filter()' function, which selectively includes elements based on a condition; reducing refers to 'reduce()' which combines all elements of an array into a single value; and sorting is handled by 'sort()', which arranges the array elements in a specified order. As such, the unique purpose of 'map()' clearly aligns with the correct choice.