Vue.js update array, not reloading all data

Question

I'm new to Vue.js and JavaScript. I just want to know how to update array (on Add/Edit/Delete) and not reloading again all the data. Only loading all data when opening page with Addresses.

This is my code:

<template v-else>
<div>
    <div class="page-header with-actions">
        <h1>Addresses</h1>
        <div class="actions">
            <b-btn @click="addAddress" variant="primary"><i class="oi oi-plus"></i> Add Address</b-btn>
        </div>
    </div>
    <div v-if="isLoaded === true">
        <div v-if="addressList.length">
            <b-form @submit.prevent="submit">
                <validation-summary :errors="errors"></validation-summary>

                <div class="row">
                    <div class="col-sm-4" v-for="address in addressList">
                        <div class="card bg-light mb-4">
                            <div class="card-header">
                                {{address.countryName}}
                                <div class="float-right">
                                    <b-btn @click="editAddress(address.id)" class="btn btn-default btn-sm" data-toggle="tooltip" title="Edit address">
                                        <i class="fa fa-edit" aria-hidden="true"></i>
                                    </b-btn>
                                    <b-btn @click="deleteAddress(address.id)" class="btn btn-default btn-sm" data-toggle="tooltip" title="Delete address">
                                        <i class="fa fa-trash" aria-hidden="true"></i>
                                    </b-btn>
                                </div>
                            </div>
                            <div class="card-body">
                                <em class="card-text">{{address.city}},</em><br />
                                <em class="card-text">{{address.streetAddress}},</em><br />
                                <em class="card-text">{{address.zip}}</em><br />
                            </div>
                        </div>
                    </div>
                </div>
            </b-form>
        </div>
        <div v-else class="alert alert-info" role="alert">
            There are no <strong>addresses</strong> yet!
        </div>
    </div>
    <add-address-modal ref="addAddressModal" @success="addressAdded"></add-address-modal>
    <edit-address-modal ref="editAddressModal" @success="addressEdited></edit-address-modal>
</div>
</template>

<script>
import Vue from 'vue';
import modalFormMixin from 'mixins/modal-form-mixin';
import formMixin from 'mixins/form-mixin';
import accountService from 'services/account-service';

import AddAddressModal from './add-address-modal';
import EditAddressModal from './edit-address-modal';

export default {
    mixins: [modalFormMixin],
    mixins: [formMixin],

    components: {
        'add-address-modal': AddAddressModal,
        'edit-address-modal': EditAddressModal
    },

    data() {
        return {
            addressList: [],
            isLoaded: false,
        }
    },

    async beforeRouteEnter(to, from, next) {
        next(async (c) => await c.initData());
    },

    methods: {
        async initData() {
            await this.loadAddressList(); //when opening page

            this.isLoaded = true;
        },

        async loadAddressList() {
            this.addressList = await accountService.getAddressList();
        },

        addAddress(data) {
            this.$refs.addAddressModal.show();
        },

        editAddress(id) {
            this.$refs.editAddressModal.show(id);
        },

        async deleteAddress(id) {
            await accountService.deleteAddress(id);

            this.loadAddressList(); //need to change

            this.$root.successToast('Address deleted');
        },

        addressAdded() {
            this.loadAddressList(); //need to change

            this.$root.successToast('Address added');
        },

        addressEdited() {
            this.loadAddressList(); //need to change

            this.$root.successToast('Address edited');
        }
    }
}
</script>

So i need to change loadAddressList() because its reloading again all the addresses data after Add/Edit/Detele. What will be the best solution for this?

Answer 1

I've fallen foul of this issue before. It's to do with Reactivity and how the changes might be delayed a tick.

An example solution to your problem.

methods: {
  async loadAddressList() {
    this.addressList = await accountService.getAddressList();
    await this.$nextTick() // waits for the next event tick before completeing function.
  },
}

Take a look into Async update Queue.

Also, take a look into Array Change Detection Replacing an array does some efficient operational work to reuse the DOM elements.

Best of luck.

Answer 2

With vue 2.0 your best bet to make sure the data change trigger a dom update everytime is Vue.set with assosiative arrays (object of objects) but to be more efficient your update / create request should return the object then you can either push it in the array or use this method:

import Vue from 'vue'
createAddress(data) {
   axios.POST('your-url', data).then( address => {
       Vue.set($store.addresses, address.id, address)
   })
}

To use that you must change your array of addresses for an assosiative like this :

import Vue from 'vue'

getAddresses(state) {
   axios.GET('your-url').then(addresses => {
       addresses.forEach(address => {
            Vue.set(state.addresses, address.id, address)
       })
   })
}

You could also do that with

Object.assign(state.addresses[address.id], address)

but from my experience this sometimes does not update the dom for unknown reason.

then your address_list would have to be a computed that point to the addresses in your state management (vuex or else)

computed: {
    address_list() {
        return $store.addresses
    }
}

Answer 3

I wonder if you could make use of then ? So in your initiData method for example you could do this?

async initData() {
    this.loadAddressList()
        .then(() => {
             this.isLoaded = true;
        });
    },

It means you don't need to update the loadAddressList method and make it wait or do other functionality that it really shouldn't take responsibility for?

UPDATE: You should also ensure your loadAddressList method returns some value, since it uses the async keyword returns a promise.

async loadAddressList() {
    this.addressList = await accountService.getAddressList();
    return true
},

Then the .then() would work in your initData() method.

Also see screen shot from https://javascript.info/async-await