code: function _mergeArrayInPlace(a,b)
  {
    if ( !b || b.length === 0 )
      return;
  
    b.forEach(function(val) {
      if ( a.indexOf(val) === -1 )
        a.push(val);
    });
  }
docs: Add the items in 'b' into 'a' (modifying the 'a' array passed in), ignoring duplicates