The latest operators added to JavaScript are spread operator and rest.
Rest operator
With rest parameter, you can represent number of arguments as an array. ES6 brought rest parameter to ease the work of developers. For arguments objects, rest parameters are indicated by three dots … and preceds a parameter.
Example
Let’s see the following code snippet to define rest parameter
<html>
<body>
<script>
function addition(…numbers) {
var res = 0;
numbers.forEach(function (number) {
res += number;
});
return res;
}
document.write(addition(3));
document.write(addition(9,10,11,12,13));
</script>
</body>
</html>Spread Operator
It allow the expression expand to multiple arguments, elements, variables, etc.
Example
You can try to run the following code to learn how to work with spread operator
Live Demo
<html>
<body>
<script>
var a, b, c, d, e, f, g;
a = [10,20];
b = "rank";
c = [30, "points"];
d = "run"
// concat method.
e = a.concat(b, c, d);
// spread operator
f = [...a, b, ...c, d];
document.write(e);
document.write("<br>"+f);
</script>
</body>
</html>