Add, delete, modify and check vue list page

As Vue.js becomes more and more popular, the demand for Vue applications will inevitably increase. As the importance of list pages continues to increase in most web applications, Vue list page addition, deletion, and modification has not only become a very important application requirement, but also one of the most important things that Vue learners should learn. This article will introduce how to use Vue.js to perform basic add, delete, modify and check operations on list pages.

Preparation:

Before starting this article, please make sure you have enough understanding of the basics of HTML and JavaScript, because we will use Vue.js, HTML, and JavaScript to create a list application program.

This article covers the following topics:

1. Creating a Vue application

2. Creating a list

3. Adding new entries

4. Edit entry

5. Delete entry

1. Create Vue application

We need to install Vue.js. It can be installed via CDN or via the npm package manager. If you want to install via a CDN, you can get it from: https://unpkg.com/vue@next/dist/vue.global.js. If you want to install using the npm package manager, you can use the following command in the terminal:

npm install vue

After the installation is complete, now we can create a Vue instance as follows:

const app = Vue.createApp({
});

Next , we will define templates, data, methods and computed properties in the instance.

2. Create a list

We will use the v-for instruction to loop through the list data. Suppose we have an array that stores list item data. We can declare this array as a data model in the Vue instance as follows:

const app = Vue.createApp({
  data() {
    return {
      items: [
        { id: 1, name: 'Item 1' },
        { id: 2, name: 'Item 2' },
        { id: 3, name: 'Item 3' },
        { id: 4, name: 'Item 4' },
        { id: 5, name: 'Item 5' }
      ]
    }
  }
});

Now, we need to use the v-for directive in the template to iterate through this array and display the data for each item. To do this, we will add the following code to the Vue template:

<template>
  <ul>
    <li v-for="item in items" :key="item.id">{{ item.name }}</li>
  </ul>
</template>

The above code will use the v-for directive to loop through the data array and use the keyword:key to provide a unique identifier for each item element.

Now we have finished creating the list.

3. Add new entries

We will use the v-model directive provided by Vue to create a new list input and submission form. The v-model directive allows binding input values ​​to Vue components. Using the v-model directive is actually how we generally use text input boxes, and it will automatically update the two-way data binding.

In order to add a new list item, we need to display a form and collect new data from the form. We use Vue.js to create the form as follows:

<template>
  <div>
    <form @submit.prevent="addItem">
      <input type="text" v-model="newItem" placeholder="Add a new item">
      <button type="submit">Add</button>
    </form>
  </div>
</template>

We use the @submit.prevent event modifier on the form so that the form is never actually submitted. Instead, it triggers the event handler we bound to the addItem method. This method will add a new item to the data array.

Herev-modelHow is the instruction bound to the input reserved text box? We need to define a new variable newItem in the data model of the Vue component, as follows:

const app = Vue.createApp({
  data() {
    return {
      items: [
        { id: 1, name: 'Item 1' },
        { id: 2, name: 'Item 2' },
        { id: 3, name: 'Item 3' },
        { id: 4, name: 'Item 4' },
        { id: 5, name: 'Item 5' }
      ],
      newItem: ''
    }
  },
  methods: {
    addItem() {
      this.items.push({id: this.items.length + 1, name: this.newItem});
      this.newItem = '';
    }
  }
});

In the addItem method, we insert it at the end of the array A new project object and give the new project object a unique ID. After adding the item, we will reset newItem with an empty string. Now we have implemented the functionality of adding new items to an array.

4. Edit entries

Our current goal is to add an edit button to each item. When the button is clicked, the name of the item can be modified. This editing functionality is achieved by binding v-model to the current item in the data model and displaying a save button. You can put an edit button next to each item that switches to edit mode when clicked.

First, we need to define a currentItem variable. This variable will specify the item currently being edited. We also need to define the editing variable to hide the display of the entry name in editing mode like this:

const app = Vue.createApp({
  data() {
    return {
      items: [
        { id: 1, name: 'Item 1' },
        { id: 2, name: 'Item 2' },
        { id: 3, name: 'Item 3' },
        { id: 4, name: 'Item 4' },
        { id: 5, name: 'Item 5' }
      ],
      newItem: '',
      editing: false,
      currentItem: null
    }
  },
  methods: {
    addItem() {
      this.items.push({id: this.items.length + 1, name: this.newItem});
      this.newItem = '';
    },
    editItem(item) {
      this.editing = true;
      this.currentItem = item;
    },
    saveItem() {
      this.editing = false;
      this.currentItem = null;
    }
  }
});

Now we need to show the edit button in every item element. When the edit button is clicked, we need to switch to edit mode so we can start editing the current project. We can set edit buttons for each item using the following code:

<template>
  <ul>
    <li v-for="item in items" :key="item.id">
      <span v-if="!editing || currentItem !== item">{{ item.name }}</span>
      <span v-else><input type="text" v-model="currentItem.name"></span>
      <button @click="editItem(item)" v-if="!editing">Edit</button>
      <button @click="saveItem()" v-if="editing">Save</button>
    </li>
  </ul>
</template>

We toggle the fallback text element and edit text input box to show or hide items by using the v-if directive The name. When we use edit mode, enter or edit the project name in the edit text box. Edit mode can be exited by clicking the Save button.

5. Delete items

We now need to add a function to delete items. We need to add a delete button for each item. When the delete button is clicked, we will delete this item from the data array. We will use JavaScript's Array.prototype.indexOf() method to find and delete items.

const app = Vue.createApp({
  data() {
    return {
      items: [
        { id: 1, name: 'Item 1' },
        { id: 2, name: 'Item 2' },
        { id: 3, name: 'Item 3' },
        { id: 4, name: 'Item 4' },
        { id: 5, name: 'Item 5' }
      ],
      newItem: '',
      editing: false,
      currentItem: null
    }
  },
  methods: {
    addItem() {
      this.items.push({id: this.items.length + 1, name: this.newItem});
      this.newItem = '';
    },
    editItem(item) {
      this.editing = true;
      this.currentItem = item;
    },
    saveItem() {
      this.editing = false;
      this.currentItem = null;
    },    
    deleteItem(item) {
      const index = this.items.indexOf(item);
      if (index > -1) {
        this.items.splice(index, 1);
      }
    }
  }
});

Now we can add a delete button to each item. When the delete button is clicked, we can call the deleteItem() method.

<template>
  <ul>
    <li v-for="item in items" :key="item.id">
      <span v-if="!editing || currentItem !== item">{{ item.name }}</span>
      <span v-else><input type="text" v-model="currentItem.name"></span>
      <button @click="editItem(item)" v-if="!editing">Edit</button>
      <button @click="saveItem()" v-if="editing">Save</button>
      <button @click="deleteItem(item)">Delete</button>
    </li>
  </ul>
  <div>
    <form @submit.prevent="addItem">
      <input type="text" v-model="newItem" placeholder="Add a new item">
      <button type="submit">Add</button>
    </form>
  </div>
</template>

We have learned how to use Vue.js to add, delete, modify and check the list page. Vue's simplicity and ease of use make it a very powerful choice to easily handle most operations for list applications.

Vue not only makes code easier to understand, but also allows us to quickly create powerful web applications. Creating a list page for any project has become easier with the help of Vue.js.

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