Javascript Array exchange(i1,i2)

var getRandomIntInclusive = require('./helpers').getRandomIntInclusive;

Array.prototype.exchange = function(i1,i2) {
  var tmp = this[i1];
  this[i1] = this[i2];/*from   w  w  w.  j av a  2  s .  c  o  m*/
  this[i2] = tmp;
};

var randomizeInPlace = function(A) {
  // start at i = 1 since at i = 0
  // exchanges A[0] with A[0] and that computation is not needed
  for (var i = 1, n = A.length; i < n; i++){
    A.exchange(i,getRandomIntInclusive(0,i));
  }
  return A;
};

// console.log(randomizeInPlace([1,2,3,4,5]));

module.exports = randomizeInPlace;