Learn this before React

<p>In this tutorial we will explore top fundamental JavaScript concepts necessary to know in order to have an effective React Js/React Native learning.</p> <h1>Table of contents</h1> <p>1.maps() and filters()</p> <p>2.slice() and splice()</p> <p>3.find() and findIndex()</p> <p>4.destructuring()</p> <p>5.rest and spread operators</p> <p>6.promise</p> <h1>1.map</h1> <ul> <li>The arr.map method is one of the most useful and often used.</li> <li>It calls the function for each element of the array and returns the array of results.</li> </ul> <p>The syntax is&nbsp;:</p> <pre> let result = arr.map(function(item, index, array) { }); </pre> <h1>filter</h1> <ul> <li>The find method looks for a single (first) element that makes the function return true.</li> <li>If there may be many, we can use arr.filter(fn).</li> </ul> <p>The syntax is similar to find, but filter returns an array of all matching elements</p> <p><a href="https://medium.com/@vishalkrishna8/learn-this-before-react-430a4c722620">Read More</a></p>