Referencing Components and Elements in Vue.Js with ref Keyword

In the previous part, we have learned how to create and listen to events. We have implemented functionality for all three buttons which emit custom events named details, update and delete and now we are going to implement functionalities for these events.

This article is part of the series

For the complete series navigation visit: Vue.js Series.

To download the source code for this part, visit Details and Deleting Owner Entity Source Code.

This post is divided into several sections:

Creating Owner Details Component
Deleting the Owner Entity
Conclusion

Creating Owner Details Component

In the previous part, we have created the custom details event and an event listener for that event. In the event handler, we’ve used the id parameter from the owner object we have clicked on, and now we are going to use that id to get the owner’s details. To accomplish that, we need to create a new component in which we are going to render the owner’s data.

Let’s do exactly that.

Creating a Component

Let’s Navigate to the src/components/owner directory and create the OwnerDetails.vue file:

<template>
  <div>
    <div class="well">
      <div class="row">
        <div class="col-md-3">
          <strong>Owner name:</strong>
        </div>
        <div class="col-md-3">
          {{ owner.name }}
        </div>
      </div>
      <div class="row">
        <div class="col-md-3">
          <strong>Date of birth:</strong>
        </div>
        <div class="col-md-3">
          {{ owner.dateOfBirth }}
        </div>
      </div>
      <div
        v-if="owner.accounts && owner.accounts.length <= 2"
        class="row">
        <div class="col-md-3">
          <strong>Type of user:</strong>
        </div>
        <div class="col-md-3">
          <span class="text-success">Beginner user.</span>
        </div>
      </div>
      <div
        v-else
        class="row">
        <div class="col-md-3">
          <strong>Type of user:</strong>
        </div>
        <div class="col-md-3">
          <span class="text-info">Advanced user.</span>
        </div>
      </div>
    </div>

    <div class="row">
      <div class="col-md-12">
        <div class="table-responsive">
          <table class="table table-striped">
            <thead>
              <tr>
                <th>Account type</th>
                <th>Date created</th>
              </tr>
            </thead>
            <tbody>
              <tr
                v-for="account in owner.accounts"
                :key="account.id">
                <td>{{ account.accountType }}</td>
                <td>{{ account.dateCreated }}</td>
              </tr>
            </tbody>
          </table>
        </div>
      </div>
    </div>
  </div>
</template>
<script>
import OwnerService from '@/api-services/owner.service';

export default {
  name: 'OwnerDetails',
  data() {
    return {
      owner: {}
    };
  },
  created() {
    OwnerService.getAccounts(this.$router.currentRoute.params.id).then((response) => {
      this.owner = response.data;
    });
  }
};
</script>

<div>

<strong>Owner name:</strong>

</div>

</div>

<strong>Date of birth:</strong>

</div>

</div>

<div

v-if="owner.accounts && owner.accounts.length <= 2"

class="row">

</div>

<span class="text-success">Beginner user.</span>

</div>

<div

v-else

class="row">

</div>

<span class="text-info">Advanced user.</span>

</div>

<thead>

<tr>

<th>Account type</th>

<th>Date created</th>

</tr>

</thead>

<tbody>

<tr

v-for="account in owner.accounts"

:key="account.id">

<td>{{ account.accountType }}</td>

<td>{{ account.dateCreated }}</td>

</tr>

</tbody>

</table>

</div>

</template>

The code snippet is pretty self-explanatory but however, let’s analyze it.

Component’s Code Explanation

We have the template with some interpolations to display owner’s name, birthday, etc. There is a conditional rendering as well, which will conditionally display Beginner user or Advanced user text based on the number of accounts related to the owner entity. In the script tag, we have the created lifecycle hook in which we fetch an owner’s id from a query string with the this.$router.currentRoute.params.id expression and then fetch a data from the backend for that owner.

Implementing an API Service and Routing to the Component

Now, let’s create the getAccounts method in our OwnerService:

  ...
  delete(id) {
    return Axios.delete(`${RESOURCE_NAME}/${id}`);
  },

  getAccounts(id) {
    return Axios.get(`${RESOURCE_NAME}/${id}/account`);
  }
};

...

delete(id) {

return Axios.delete(`${RESOURCE_NAME}/${id}`);

getAccounts(id) {

return Axios.get(`${RESOURCE_NAME}/${id}/account`);

}

};

We still need to create the route for this component.

To do that, we are going to edit the src/router/index.js file:

    {
      path: '/owner/list',
      name: 'OwnerList',
      component: OwnerList
    },
    {
      path: '/owner/:id',
      name: 'OwnerDetails',
      component: OwnerDetails
    },
    {
      path: '*',
      name: 'NotFound',
      component: NotFound
    }

{

path: '/owner/list',

component: OwnerList

{

path: '/owner/:id',

component: OwnerDetails

{

path: '*',

component: NotFound

}

We have just defined a new route which will accept id as a parameter through the query string. We can access the route parameters in our components through the this.$router.currentRoute.params object.

Finally, we need to navigate to this component when we click on the Details button in the owner list table.

Let’s edit the src/components/owner/OwnerList.vue file:

    detailsOwner(ownerId) {
      this.$router.push({ name: 'OwnerDetails', params: { id: ownerId } });
    },

detailsOwner(ownerId) {

this.$router.push({ name: 'OwnerDetails', params: { id: ownerId } });

Great!

Now, we are going to open a terminal and type the npm run dev command to view results:

Everything looks perfect.

Now let’s implement the Delete functionality.

Deleting the Owner Entity

When a user clicks on the Delete button, the confirmation dialog needs to show up. If we confirm the delete action, a request will be sent to the server. The server may respond with 204 (No Content) status code which means that we have successfully deleted the owner entity.

Otherwise, the server may respond with one of the error messages, depending on what went wrong. In both outcomes, we will display a modal which will inform us if our action was successful or not.

So, let’s summarize it.

We are going to create two modals. One is confirmation modal which has a static content and the second one is a modal which will inform us about the response of the delete request. So, in the second one, we are going to implement the data binding because we need to display different messages depending on the server response.

Creating a Component

Let’s navigate to the OwnerList.vue component and implement that data binding action:

<template>
  <div>
    <b-row>
      <b-col
        md="2"
        offset-md="10">
        <a href="#">Create owner</a>
      </b-col>
    </b-row>
    <br>
    <b-row>
      <b-col md="12">
        <div class="table-responsive">
          <table class="table table-striped">
            <thead>
              <tr>
                <th>Owner name</th>
                <th>Owner address</th>
                <th>Date of birth</th>
                <th>Details</th>
                <th>Update</th>
                <th>Delete</th>
              </tr>
            </thead>
            <tbody>
              <owner-list-row
                v-for="owner in owners"
                :key="owner.id"
                :owner="owner"
                @details="detailsOwner"
                @update="updateOwner"
                @delete="deleteOwner"/>
            </tbody>
          </table>
        </div>
      </b-col>
    </b-row>
    <b-modal
      ref="deleteConfirmModal"
      title="Confirm your action"
      @ok="onDeleteConfirm"
      @hide="onDeleteModalHide">
      <p class="my-4">Are you sure you want to delete this owner?</p>
    </b-modal>

    <b-modal
      ref="alertModal"
      :title="alertModalTitle"
      :ok-only="true">
      <p class="my-4">{{ alertModalContent }}</p>
    </b-modal>
  </div>
</template>
<script>
import OwnerService from '@/api-services/owner.service';
import OwnerListRow from '@/components/owner/OwnerListRow';

export default {
  name: 'OwnerList',
  components: {
    OwnerListRow
  },
  data() {
    return {
      owners: [],
      selectedOwnerId: null,
      alertModalTitle: '',
      alertModalContent: ''
    };
  },
  created() {
    this.fetchOwners();
  },
  methods: {
    detailsOwner(ownerId) {
      this.$router.push({ name: 'OwnerDetails', params: { id: ownerId } });
    },
    updateOwner(ownerId) {
      console.log('update', ownerId);
    },
    deleteOwner(ownerId) {
      this.selectedOwnerId = ownerId;
      this.$refs.deleteConfirmModal.show();
    },
    fetchOwners() {
      OwnerService.getAll().then((response) => {
        this.owners = response.data;
      });
    },
    onDeleteConfirm() {
      OwnerService.delete(this.selectedOwnerId).then(() => {
        this.alertModalTitle = 'Successfully';
        this.alertModalContent = 'Successfully deleted Account Owner';
        this.$refs.alertModal.show();
        this.fetchOwners();
      }).catch((error) => {
        this.alertModalTitle = 'Error';
        this.alertModalContent = error.response.data;
        this.$refs.alertModal.show();
      });
    },
    onDeleteModalHide() {
      this.selectedOwnerId = null;
    }
  }
};
</script>

<div>

<b-row>

<b-col

md="2"

offset-md="10">

<a href="#">Create owner</a>

</b-col>

</b-row>

<br>

<b-row>

<b-col md="12">

<thead>

<tr>

<th>Owner name</th>

<th>Owner address</th>

<th>Date of birth</th>

<th>Details</th>

<th>Update</th>

<th>Delete</th>

</tr>

</thead>

<tbody>

<owner-list-row

v-for="owner in owners"

:key="owner.id"

:owner="owner"

@details="detailsOwner"

@update="updateOwner"

@delete="deleteOwner"/>

</tbody>

</table>

</div>

</b-col>

</b-row>

<b-modal

ref="deleteConfirmModal"

title="Confirm your action"

@ok="onDeleteConfirm"

@hide="onDeleteModalHide">

<p class="my-4">Are you sure you want to delete this owner?</p>

</b-modal>

<b-modal

ref="alertModal"

:title="alertModalTitle"

:ok-only="true">

<p class="my-4">{{ alertModalContent }}</p>

</b-modal>

</div>

</template>

First, let’s analyze the script part.

Component’s Code Explanation

We have moved a fetch owner logic from the created lifecycle hook to the method named fetchOwners. That’s because we need to fetch all the owners again after we successfully delete one owner. Now that we’ve moved the logic to the method, we can reuse our fetch owner code.

Next up, we create some data variables. In the selectedOwnerId variable we are going to store the id parameter from the owner entity we want to delete. In the remaining two variables we will store the title and the content for the second modal.

Let’s take a look at the this.$refs statement. We use it for the first time and we are going to explain it right now.

In the template part, we have two modals. On both modals, we have the ref=”something” attribute. Just as we can get an element in a vanilla JavaScript with the document.getElementById() expression, we can get a reference to the element (or another vue component, b-modal in this case) in the Vue.js by using the ref and this.$refs statements. We can use these references to the modals to trigger the show() method inside them. The rest of the template is also self-explanatory.

Inspecting the Results

Let’s again open a terminal and run the npm run dev command to view results.

If we try to delete Anna Bosh, the confirmation modal will show up:

When we click on the OK button, the error appears because Anna Bosh have the related accounts:

If we try to delete Nick Somion, the confirmation dialogue shows up again:

And the successfully message shows up:

Conclusion

By reading this post you’ve learned:

How to handle server errors
How to reference elements or components from the template
And how to create a confirmation dialogue

In the next part of the series, we are going to implement creating and deleting the Account Owner and with that, we are finalizing or application development.

4 Comments

Piyush on May 24, 2020 at 8:40 pm

Access to XMLHttpRequest at ‘https://localhost:44374/api/owner/f522ca62-186d-4c38-af0e-7b9302d30295’ from origin ‘http://localhost:8080’ has been blocked by CORS policy: Method DELETE is not allowed by Access-Control-Allow-Methods in preflight response.
- Piyush on May 24, 2020 at 11:52 pm
  
  sservices.AddCors(options => { options.AddPolicy("CorsPolicy", builder => builder.AllowAnyOrigin() .AllowAnyMethod() .AllowAnyHeader() ); });
  i dont think there is an issue with the cors on asp.net core can’t get where am i missing out
- Piyush on May 25, 2020 at 1:22 am
  
  Getting the same issue for POST and PUT though i am able to get data
  Postman is working fine with all requests
- Piyush on May 25, 2020 at 6:56 am
  
  Had issues with app.UseCors(); in startup file didn’t pass the policy name adding policy name workedapp.UseCors("CorsPolicy");
  thanks for the great tutorials

Creating Vue.js Client Side – Using ref Keyword to Reference Components (Details and Delete Components)

Creating Owner Details Component

Creating a Component

Component’s Code Explanation

Implementing an API Service and Routing to the Component

Deleting the Owner Entity

Creating a Component

Component’s Code Explanation

Inspecting the Results

Conclusion

4 Comments

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