Using .map(), .reduce() and .filter() in JavaScript
Useful links: https://code.tutsplus.com/tutorials/how-to-use-map-filter-reduce-in-javascript--cms-26209 https://medium.com/poka-techblog/simplify-your-javascript-use-map-reduce-and-filter-bd02c593cc2d To summarize: map Creates a new array by transforming every element in an array, individually. filter Creates a new array by removing elements that don't belong. reduce Takes all of the elements in an array, and reduces them into a single value. reduce method executes a provided function for each value of the array (from left-to-right). reduce passes your callback four arguments: The current value The previous value The current index The array you called reduce on In this post I use playcode.io to do the compiling of the JavaScripts online. Example Suppose we have the following array of objects, and we wish to filter the list of objects whose age is greater than 12, put the ages of those filtered objects into another array, and find the total age f...