The Spread operator is a little-known operator which allows you to join arrays together. This might sound similar to the join() function but the difference is that the join() function returns the array as a string, whereas the spread operator returns it as an array.
The spread operator is represented by three dots …
The sample code below shows it in action
<html> <head><title>Spread Operator</title></head> <script> let arr1 = [1,2,3]; let arr2 = [4.5,6.09,10.001]; var arr3 = ["one", "two", "three"]; let arr4 = [...arr1, ...arr2, ...arr3]; document.write(arr4); </script> <body> </body> </html>
The output is shown below