Метод в компоненте

<template>
  <div>


<div class="row flex-nowrap test">
    <div v-if="halls" v-for="hall in halls" class="col-3 col-lg-3">
        <div class="card">
            <div class="card-body">
                <a href="#" @click.prevent="getHallAtributes(hall.id)">{{ hall.name }}</a> 
                <span class="badge badge-primary ml-3 mb-2">5</span>
                <i @click="showCalendar(hall.id)" class="pointer fe fe-calendar h2 ml-3 mb-0 text-muted"></i>
            </div>
        </div>
    </div>
</div>


<div class="row">
    <div class="col-12">
        <div class="card">
            <div class="card-body">
                <table class="table table-bordered datatable datatable-User table-collection">
                    <tbody>
                        <tr>
                            <td class="pt-2 pb-2 col-3 text-center h3">
                                {{ this.monthNames[new Date(this.year, this.month).getMonth() - 1] }}, {{ this.year }}
                            </td>
                            <td  v-for="n in dates" :style="[n.getDay() === 0 || n.getDay() === 6 ? { 'background-color': 'red', color: 'white' } : { color: 'black' },]" class="pt-2 pb-2 text-center">{{ n.getDate() }}
                            </td>
                        </tr>

                        <template v-for="val in hall.schedule_hall">
                            <tr>
                                <td class="bg-primary text-white">{{ val.time }}:00 - {{ val.programm.name }}
                                <i class="fe fe-plus ml-4"></i>
                            </td>
                            </tr>
                            <template v-for="vals in val.programm.children">
                                {{ computedUserData([vals]) }}
                                <tr v-for="user in selectedUsers" :key="user.id">
                                    <td class="pt-2 pb-2 col-3">
                                        <span class="ml-3">{{ user.surname }}</span>
                                        <span class="ml-1">{{ user.name }}</span>
                                        <span class="ml-4">{{ user.year }}</span>
                                    </td>
                                    <td v-for="(n, index) in daysInMonth" class="pt-2 pb-2 text-center order-left-0 border-white grey">
                                        <i v-if="user.journal[n]" :class="user.journal[n]"></i>
                                    </td>
                                </tr>
                            </template>
                        </template>

                    </tbody>
                </table>
            </div>
        </div>
    </div>
</div>

  </div>
</template>

<script>

  export default {
    data() {
        return {
            selectedUsers: [],
                    options: [
          { value: 'A', text: 'Option A (from options prop)' },
          { value: 'B', text: 'Option B (from options prop)' }
        ],
            monthNames: [
                "Январь", "Февраль", "Март", "Апрель", "Май", "Июнь",
                "Июль", "Август", "Сентябрь", "Октябрь", "Ноябрь", "Декабрь"
            ],
            days: [
                "Понедельник", "Вторник", "Среда", "Четверг", "Пятница", "Суббота", "Воскресенье"
            ],

            programms: [
                "Зирка Лева", "Вперед до зирок", "Мастер команды"
            ],

            time: [
                "1", "2", "3", "4"
            ],
            halls: [],
            children: [],
            child: '',
            hall: {
                schedule_hall: {},
                programm: {},
            },
            namegroup: '',
            programm_id: '',
            category_time: '',
            dataVm: '',
            n: 8,
            year: 2020,
            month: 6,
            row: null,
            rowid: null,
        }
    },

      created() {

        this.getHalls();

      },

     computed: {
        daysInMonth(month,year) {
            return new Date(this.year, this.month, 0).getDate();
        },
        dates() {
            return new Array(this.daysInMonth).fill(1).map((_, index) => new Date(this.year, this.month - 1, index + 1))
        }
     },

    methods: {
        computedUserData(vals) {
            this.selectedUsers = vals.reduce((res, item) => {
              const tempItem = {
                id: item.id,
                surname: item.child_surname,
                name: item.child_name,
                journal: {}
              }
              
              tempItem.journal = item.journal.reduce((carry, {day, icon}) => {
                carry[day] = icon;
                return carry;
              }, {});
              res.push(tempItem)
              return res;
            }, []);
        },

        // Получаем список существующих залов и при условии наличии узнаем id первого элемента из массива и передаем параметр в метод
        getHalls() {
            axios.get('api/v2/halls')
            .then(response => this.halls = response.data.data)
            if (this.halls) {
                setTimeout(() => {
                    this.halls ? this.getHallAtributes(this.halls[0].id) : null;
                },500)  
            }

        },

        // Запускаем эмулятор загрузки, получаем атрибуты зала по его id
        getHallAtributes(hall) {
            let loader = this.$loading.show({
              container: this.fullPage ? null : this.$refs.formContainer,
              color: '#0080ff',
            });
            axios.get('api/v2/halls/' + hall)
            .then(response => this.hall = response.data.data)
                setTimeout(() => {
                    loader.hide()
                    },500) 
        },

    }
  }

</script>

Вот что приходит в hall

{
  "id": 1,
  "branch_id": 1,
  "name": "Большой зал",
  "created_at": null,
  "updated_at": "2020-06-16 10:27:36",
  "schedule_hall": [
    {
      "id": 1,
      "hall_id": 1,
      "programm_id": 2,
      "day": 1,
      "time": 8,
      "category_time": 1,
      "total_children": 20,
      "created_at": null,
      "updated_at": null,
      "programm": {
        "id": 2,
        "name": "Вперед до зірок",
        "branch_id": 1,
        "created_at": "2020-05-20 18:33:12",
        "updated_at": "2020-05-22 23:39:30",
        "children": [
          {
            "id": 14,
            "child_surname": "Турцевич",
            "child_name": "Артём",
            "programm_id": 2,
            "journal": [
              {
                "id": 1,
                "base_id": 14,
                "day": 16,
                "icon": "fe fe-alert-circle text-warning",
                "created_at": null,
                "updated_at": null
              },
              {
                "id": 2,
                "base_id": 14,
                "day": 20,
                "icon": "fe fe-sun text-primary",
                "created_at": null,
                "updated_at": null
              },
              {
                "id": 5,
                "base_id": 14,
                "day": 11,
                "icon": "fe fe-alert-circle text-warning",
                "created_at": "2020-06-22 06:45:29",
                "updated_at": "2020-06-22 06:45:29"
              },
              {
                "id": 29,
                "base_id": 14,
                "day": 30,
                "icon": "fe fe-alert-circle text-warning",
                "created_at": "2020-06-22 12:52:24",
                "updated_at": "2020-06-22 12:52:24"
              },
              {
                "id": 42,
                "base_id": 14,
                "day": 1,
                "icon": "fe fe-sun text-primary",
                "created_at": "2020-06-22 13:22:34",
                "updated_at": "2020-06-22 13:22:34"
              }
            ]
          },
          {
            "id": 16,
            "child_surname": "Григорян",
            "child_name": "Эдмон",
            "programm_id": 2,
            "journal": [
              {
                "id": 3,
                "base_id": 16,
                "day": 5,
                "icon": "fe fe-x text-danger",
                "created_at": null,
                "updated_at": null
              },
              {
                "id": 30,
                "base_id": 16,
                "day": 30,
                "icon": "fe fe-alert-circle text-warning",
                "created_at": "2020-06-22 12:52:25",
                "updated_at": "2020-06-22 12:52:25"
              },
              {
                "id": 34,
                "base_id": 16,
                "day": 26,
                "icon": "fe fe-sun text-primary",
                "created_at": "2020-06-22 12:52:54",
                "updated_at": "2020-06-22 12:52:54"
              }
            ]
          },
          {
            "id": 17,
            "child_surname": "Сильченко",
            "child_name": "Максим",
            "programm_id": 2,
            "journal": [
              {
                "id": 31,
                "base_id": 17,
                "day": 30,
                "icon": "fe fe-alert-circle text-warning",
                "created_at": "2020-06-22 12:52:27",
                "updated_at": "2020-06-22 12:52:27"
              },
              {
                "id": 43,
                "base_id": 17,
                "day": 10,
                "icon": "fe fe-alert-circle text-warning",
                "created_at": "2020-06-22 13:23:11",
                "updated_at": "2020-06-22 13:23:11"
              },
              {
                "id": 46,
                "base_id": 17,
                "day": 19,
                "icon": "fe fe-sun text-primary",
                "created_at": "2020-06-22 13:24:39",
                "updated_at": "2020-06-22 13:24:39"
              }
            ]
          },
          {
            "id": 19,
            "child_surname": "Соколовская",
            "child_name": "София",
            "programm_id": 2,
            "journal": [
              {
                "id": 28,
                "base_id": 19,
                "day": 24,
                "icon": "fe fe-sun text-primary",
                "created_at": "2020-06-22 12:51:15",
                "updated_at": "2020-06-22 12:51:15"
              },
              {
                "id": 32,
                "base_id": 19,
                "day": 30,
                "icon": "fe fe-sun text-primary",
                "created_at": "2020-06-22 12:52:28",
                "updated_at": "2020-06-22 12:52:28"
              },
              {
                "id": 35,
                "base_id": 19,
                "day": 14,
                "icon": "fe fe-sun text-primary",
                "created_at": "2020-06-22 12:53:08",
                "updated_at": "2020-06-22 12:53:08"
              },
              {
                "id": 44,
                "base_id": 19,
                "day": 19,
                "icon": "fe fe-alert-circle text-warning",
                "created_at": "2020-06-22 13:23:45",
                "updated_at": "2020-06-22 13:23:45"
              }
            ]
          },
          {
            "id": 21,
            "child_surname": "Иванов",
            "child_name": "Дмитрий",
            "programm_id": 2,
            "journal": [
              {
                "id": 26,
                "base_id": 21,
                "day": 1,
                "icon": "fe fe-alert-circle text-warning",
                "created_at": "2020-06-22 12:50:17",
                "updated_at": "2020-06-22 12:50:17"
              },
              {
                "id": 27,
                "base_id": 21,
                "day": 1,
                "icon": "fe fe-sun text-primary",
                "created_at": "2020-06-22 12:50:41",
                "updated_at": "2020-06-22 12:50:41"
              },
              {
                "id": 33,
                "base_id": 21,
                "day": 30,
                "icon": "fe fe-sun text-primary",
                "created_at": "2020-06-22 12:52:29",
                "updated_at": "2020-06-22 12:52:29"
              },
              {
                "id": 36,
                "base_id": 21,
                "day": 8,
                "icon": "fe fe-alert-circle text-warning",
                "created_at": "2020-06-22 12:54:02",
                "updated_at": "2020-06-22 12:54:02"
              }
            ]
          }
        ]
      }
    },
    {
      "id": 2,
      "hall_id": 1,
      "programm_id": 3,
      "day": 1,
      "time": 10,
      "category_time": 7,
      "total_children": 12,
      "created_at": null,
      "updated_at": null,
      "programm": {
        "id": 3,
        "name": "Народження зірки",
        "branch_id": 1,
        "created_at": "2020-05-20 18:33:23",
        "updated_at": "2020-05-22 23:39:11",
        "children": [
          {
            "id": 22,
            "child_surname": "Шевченко",
            "child_name": "Максим",
            "programm_id": 3,
            "journal": [
              {
                "id": 37,
                "base_id": 22,
                "day": 24,
                "icon": "fe fe-sun text-primary",
                "created_at": "2020-06-22 12:54:46",
                "updated_at": "2020-06-22 12:54:46"
              },
              {
                "id": 38,
                "base_id": 22,
                "day": 1,
                "icon": "fe fe-sun text-primary",
                "created_at": "2020-06-22 12:54:50",
                "updated_at": "2020-06-22 12:54:50"
              },
              {
                "id": 39,
                "base_id": 22,
                "day": 11,
                "icon": "fe fe-alert-circle text-warning",
                "created_at": "2020-06-22 12:55:47",
                "updated_at": "2020-06-22 12:55:47"
              },
              {
                "id": 40,
                "base_id": 22,
                "day": 18,
                "icon": "fe fe-sun text-primary",
                "created_at": "2020-06-22 12:56:04",
                "updated_at": "2020-06-22 12:56:04"
              },
              {
                "id": 41,
                "base_id": 22,
                "day": 28,
                "icon": "fe fe-sun text-primary",
                "created_at": "2020-06-22 13:16:16",
                "updated_at": "2020-06-22 13:16:16"
              },
              {
                "id": 45,
                "base_id": 22,
                "day": 6,
                "icon": "fe fe-alert-circle text-warning",
                "created_at": "2020-06-22 13:23:49",
                "updated_at": "2020-06-22 13:23:49"
              }
            ]
          }
        ]
      }
    }
  ]
}