JSFiddle - React, Tailwind, and code Playground

JavaScript

function sumAll(arr) {

var y =[];
var x = Math.min(arr[0],arr[1]);
y.unshift(x);
while (x<Math.max(arr[0],arr[1]))
{x++;
y.push(x);}

var m = y.reduce(function(n1,n2){
return n1+n2;
});
console.log(m);
}

sumAll([10, 5]);