Javascript Array binarySearchRecurse(target)

Array.prototype.binarySearchRecurse = function(target) {
  var half = Math.floor(this.length/2);

  if (target === this[half]) {
    return half;/* w  ww . ja va  2 s  .  c  om*/
  } else if (this.length === 1) {
    return null;
  }

  if (target > this[half]) {
    return this.splice(half, this.length).binarySearchRecurse(target);
  } else {
    return this.splice(0, half).binarySearchRecurse(target);
  }
};

Array.prototype.binarySearchRecurse = function(val) {

  var initArray = this.slice();
  var result;/*  w w  w  .j  av  a 2s. c o  m*/

  var recurse = function(firstHalf) {

    if (firstHalf.length === 1) {
      result = firstHalf[0] === val;
      return;
    }

    var arrayHalfIndex = Math.floor(firstHalf.length/2);

    var secondHalf = firstHalf.splice(arrayHalfIndex, firstHalf.length - 1);

    if (val < secondHalf[0]) {
      if (firstHalf[0] === val) {
        result = true
        return;
      }
      recurse(firstHalf);
    } else {
      if (secondHalf[0] === val) {
        result = true;
        return;
      }
      recurse(secondHalf);
    }
  }
  recurse(initArray);

  return result;
};


  //val = 3
  //[1,2,3,4,5]
  // [1,2,3] & [4,5]
  //val < [4,5][0] === true
  //call recursion with firstHalf
  //[1] & [2,3]
  //val < [2,3][0] === false
  //call recursion with secondHalf
  //[3] & [2]
  //val === [2][0]


  // var firstHalf = this.slice();
  // var secondHalf;