JavaScript array.flatMap()

JavascriptObject Oriented ProgrammingWeb DevelopmentFront End Technology

The array.flatMap() method of JavaScript is used to flatten the input array element into a new array.

The syntax is as follows −

array.flatMap(function callback(current_value, index, Array))

Let us now implement the array.flatMap() method in JavaScript −

Example

 Live Demo

<!DOCTYPE html>
<html>
<body>
   <h2>Ranking Points</h2>
   <p>Is any point equal to 550 from the key-value pairs...</p>
   <button onclick="display()">Result</button>
   <p id="test"></p>
   <script>
      var pointsArr = [10, 20, 30, 40, 50, 60, 70, 80, 90, 1000];
      var res = pointsArr.flatMap(val => [val + 10]).entries();
      for (val of res) {
         document.getElementById("test").innerHTML += val + "<br>";
      }
      function pointsFunc(points) {
         return points == 550;
      }
      function display() {
         document.getElementById("test").innerHTML = pointsArr.some(pointsFunc);
      }
   </script>
</body>
</html>

Output

Click the “Result” button above −

Example

 Live Demo

<!DOCTYPE html>
<html>
<body>
   <h2>Car Variant</h2>
   <button onclick="display()">Result</button>
   <p id="test"></p>
   <script>
      var carid = ["110", "230", "299", "399"];
      var res = carid.flatMap(val => [val + 10]).entries();
      for (val of res) {
         document.getElementById("test").innerHTML += val + "<br>";
      }
      function display() {
         document.getElementById("test").innerHTML = "Array after slicing some elements =    "+carid.slice(1,4);
      }
   </script>
</body>
</html>

Output

Click the “Result” button −

raja
Published on 17-Dec-2019 12:55:08
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