How to use spread operator to join two or more arrays in JavaScript?
Two join two or more arrays we have a built-in method called array.concat(). But we can join arrays much more easily by using spread operator.
Syntax
var merged = [...arr1, ...arr2];
Lets' try to merge arrays without spread operator.
In the following example, instead of the spread operator, array.concat() method is used to join two arrays.
Example
Live Demo
<html>
<body>
<script>
var arr1 = [1,2,3];
var arr2 = [4,5,6];
var merged = arr1.concat(arr2);
document.write(merged);
</script>
</body>
</html>
Output
1,2,3,4,5,6
Spread operator
In the following example, spread operator is used to join two arrays.
Example
Live Demo
<html>
<body>
<script>
var arr1 = [1,2,3];
var arr2 = [4,5,6];
var merged = [...arr1, ...arr2];
document.write(merged);
</script>
</body>
</html>
Output
1,2,3,4,5,6
In the following example, spread operator is used to join 3 arrays. By using concat() method it is difficult if there are more arrays but by using spread operator it is very easy to join more number arrays.
Example
Live Demo
<html>
<body>
<script>
var arr1 = [1,2,3];
var arr2 = [4,5,6];
var arr3 = [7,8,9];
var merged = [...arr1,...arr2,...arr3];
document.write(merged);
</script>
</body>
</html>
Output
1,2,3,4,5,6,7,8,9
Published on 03-Jul-2019 12:10:10
