My solution to Project Euler problem 5, using map and reduce.

solution.js

//QUESTION
//2520 is the smallest number that can be divided by each of the numbers from 1 to 10 without any remainder.
//What is the smallest positive number that is evenly divisible by all of the numbers from 1 to 20?

//SOLUTION
// change to 10 to check against PE example
var end = 20;

//generate sequence
var arrSeq = Array
  .apply(null, Array(end))
  .map(Function.prototype.call.bind(Number))
  .map(function(x) { return x + 1; } );

//masterArray will hold the final list of factors to be multiplied together to get the result
var masterArray = new Array(0);

//
function factorise(x) {
    var tempArray = Object.create(masterArray);  //copy masterArray to tempArray
    while (x > 1 && tempArray.length > 0)  {
        //if factor found, recalculate x to x/factor
        if (!(x % tempArray[tempArray.length - 1])) {
            x = x / tempArray[tempArray.length - 1];
        }
        tempArray.pop();  //remove last element in tempArray and go back to start of loop
    }
    masterArray.push(x);  //add x to masterArray
    return x;
    }

//define function to reduce list of factors to final result
function multiply(r, c) {
 return r * c;   
}

//perform calculation
var result = arrSeq
  .map(factorise)
  .reduce(multiply, 1);

//output array of factors and final result
console.log(masterArray);
console.log(result);