biggestSumOfTwoElements.js

//es5
function biggestSumOfTwoElements(array){
    if (array.length===0){ return false;}
    else if(array.length===1){ return array[0];}
    else{
        array.sort(function(a, b){return a-b}); 
        return array[array.length-1]+array[array.length-2];
    }
}

//es6 one-liner
const biggestSumOfTwoElements = (a) => (a.length)?false:a.length===1?a[0]:a.sort()[a.length - 1] + a.sort()[a.length - 2];

//es5 one-liner
var biggestSumOfTwoElements = function biggestSumOfTwoElements(array) {return array.length === 0 ? false : array.length === 1 ? array[0] : array.sort()[array.length - 1] + array.sort()[array.length - 2];};