let objArr =  [{key:'value',id:1},{key:'value2',id:1},{key:'value3',id:2},{key:'value4',id:2}];
let newArr = [];
let tempArrPair = [];
objArr.forEach(item=>{
  if(tempArrPair.length==0 || tempArrPair[0].id==item.id){
    tempArrPair.push(item);
  }

  if(tempArrPair.length>1){
    newArr.push(tempArrPair);
    tempArrPair = [];
  }
});ja