尝试访问 object 中的值时，javascript 变量未定义错误？

Question

  const roomAndReservationBinding = (rooms, reservations) => {
    var roomInfo = rooms;
    for (var i = 0; i <= roomInfo.length; i++) {
      var room = roomInfo[i];

      console.log(room.id);
    }
  };

// on console i get the IDs printed as expected, but on the browser i get the following error, room is undefined on the line of console.log() function

Answer 1

This is the root cause -:

for (var i = 0; i <= roomInfo.length; i++) {

You are iterating one extra time, it should be this -:

for (var i = 0; i < roomInfo.length; i++) {

 const roomAndReservationBinding = (rooms, reservations) => { var roomInfo = rooms; for (var i = 0; i < roomInfo.length; i++) { var room = roomInfo[i]; console.log(room.id); } }; roomAndReservationBinding([{id:1},{id:2},{id:3}],[])