判断数组中是否包含某个id的对象

getRepeatId (arr, id) {
  var index = arr.findIndex(item => item.id=== id)
  return index  // -1 说明arr中不存在id为传入id的对象
}

const arr = [{id: 1},{id: 2},{id: 3},{id: 4},{id: 5}]
this.getRepeatId(arr, 1)
this.getRepeatId(arr, 6)