Vuetify Data tables render nested data

Question

I have the following JSON data:

[
  {
    "amount": 75,
    "date": "2020-04-22",
    "entradas": [
      {
        "date": "2020-04-22",
        "amount": "100.00",
        "title": "test 1"
      },
      {
        "date": "2020-04-22",
        "amount": "-25.00",
        "title": "test 2"
      }
    ]
  },
  {
    "amount": 10,
    "date": "2020-04-30",
    "entradas": [
      {
        "date": "2020-04-30",
        "amount": "10.00",
        "title": "test 3"
      }
    ]
  }
]

What I would like to achieve is render all these "entradas" records together, so in this case it should render 3 rows at the Data Table, one for each "entradas".

I have the following basic method to load the json by axios:

    methods: {
        loadData () {
            axios.get('dataapi')
                    .then(response => this.dataItems = response.data)
        },
    }

and

    data () {
        return {
            headers: [
                {
                    text: 'Data',
                    align: 'start',
                    sortable: false,
                    value: 'date',
                },
                { text: 'Title', value: 'title', sortable: false },
                { text: 'Amount', value: 'amount', sortable: false },
            ],
            dataItems: []
        }
    },

<template>
    <v-app id="testdatatable">
        <v-data-table
        :headers="headers"
        :items="dataItems.entradas"
        class="elevation-1"
        ></v-data-table>
    </v-app>
</template>

The problem is that when I use :items="dataItems.entradas" it just doesn't render anything. The same problems happens if I use just :items="dataItems" and at the headers use something like value: 'entradas.title'

I've tried some workaround with .map function, as I've seem some similar examples, but I didn't figured out how could that help in this situation...

Answer 1

You should only need a simple reduce to flatten the nested item arrays..

  methods: {
        loadData () {
            axios.get('dataapi')
                  .then((response) => {
                      this.dataItems = response.data.reduce(function(acc, v) {
                             return [...acc, ...v.entradas]
                      },[])
                  })
        },
    }

  <v-data-table
    :headers="headers"
    :items="dataItems"
    class="elevation-1"
  ></v-data-table>

Demo (see flatItems() computed)

Answer 2

Try this

...
data () {
    return {
        headers: [
            {
                text: 'Data',
                align: 'start',
                sortable: false,
                value: 'date',
            },
            { text: 'Title', value: 'title', sortable: false },
            { text: 'Amount', value: 'amount', sortable: false },
        ],
        dataItems: [],
    }
},
methods: {
    loadData () {
        axios
            .get('dataapi')
            .then(response => {
                this.dataItems = response.data.map(dataItem => {
                    const { amount, date, entradas } = dataItem

                    entradas.map(entrada => {
                        return {
                            amount, 
                            date,
                            ...entrada
                        }
                    })
                })
            })
    },
}
...
<template>
    <v-app id="testdatatable">
        <v-data-table
            :headers="headers"
            :items="dataItems"
            class="elevation-1"
        ></v-data-table>
    </v-app>
</template>