Solutions to questions at http://toys.usvsth3m.com/javascript-under-pressure/. I can JavaScript under pressure in 4 min 55 secs

jsUnderPressureSolutions.js

/** 
 * Solutions to questions at {@link http://toys.usvsth3m.com/javascript-under-pressure/ }
 */

// Ans 1
function doubleInteger(i){
  return i*2;
}


// Ans 2
function isNumberEven(i){
  return i%2 == 0;
}


// Ans 3
function getFileExtension(i){
  var rawExt = i.match(/\.+[a-zA-Z0-9]+/),
      ext = false;

  if(rawExt && rawExt.length){
    ext = rawExt[0].substring(1);
  }
  
  return ext;
}


// Ans 4
function longestString(i){
  for(var x = i.length - 1; x>=0; --x){
    if(typeof i[x] != 'string'){
      i[x] = "";
    }
  }
  
  i.sort(function(a,b){
    return b.length - a.length;
  });
  
  return i[0];
}


// Ans 5
function arraySum(i){
  var sum=0,
      x = i.length - 1,
      val;
      
  for(; x>=0; --x){
    val = i[x];
    
    switch(typeof val){
      case "number" : sum += val; break;
      case "object" : sum += arraySum(val); break;
    }
  }
  
  return sum;
}