DNA Pairing

function pair(str) {
  //return str;
  var arr = str.split(‘‘);
  var pait = ‘‘;
  var result = arr.map(function(item,index,array){
    if(item === ‘A‘){
      pait = ‘T‘;
    }else if(item === ‘C‘){
      pait = ‘G‘;
    }else if(item === ‘G‘){
      pait = ‘C‘;
    }else if(item === ‘T‘){
      pait = ‘A‘;
    }
    return [item,pait];
  });
  return result;
}

pair("GCG");