Ways to add the class "active" to the initial element in a Vue.js for loop

Question

Ways to add the class "active" to the initial element in a Vue.js for loop

I am currently diving into learning vue.js and am working on adding a list of elements. My goal is to apply the class="active" only to the first element in the for loop. Below is the snippet of my code:

<div class="carousel-inner text-center " role="listbox">
    <div class="item" v-for="sliderContent in sliderContents">
        <h1>{{ sliderContent.title }}</h1>
        <p v-html="sliderContent.paragraph"></p>
    </div>
</div>

This is how I want the first element to appear:

<div class="item active">
    <h1>WELCOME TO CANVAS</h1>
    <p>Create just what you need for your Perfect Website. Choose from a wide<br>range of Elements & simply put them on your own Canvas</p>
</div>

The data retrieval process is functioning correctly, so all seems to be in order.

Below is my script code:

<script>
export default{
    data() {
        return {
            sliderContents: [
                {
                    title: "WELCOME TO CANVAS",
                    paragraph: "Create just what you need for your Perfect Website. Choose from a wide<br>range of Elements & simply put them on your own Canvas"
                },
                {
                    title: "WELCOME TO CANVAS",
                    paragraph: "Create just what you need for your Perfect Website. Choose from a wide<br>range of Elements & simply put them on your own Canvas"
                },
                {
                    title: "WELCOME TO CANVAS",
                    paragraph: "Create just what you need for your Perfect Website. Choose from a wide<br>range of Elements & simply put them on your own Canvas"
                },
                {
                    title: "WELCOME TO CANVAS",
                    paragraph: "Create just what you need for your Perfect Website. Choose from a wide<br>range of Elements & simply put them on your own Canvas"
                }
            ]
        }
    }
}

Your assistance would be greatly appreciated!

javascript vuejs2 vue.js

Answer 1

Answer №1

const TitleComponent = {
  template: `
    <h1>{{ title }}</h1>
  `,
  
  props: ['title'],
};

new Vue({
  components: {
    TitleComponent,
  },
  
  template: `
    <div>
      <title-component
        v-for="(item, index) in items"
        :class="{ 'active': index === 0 }"
        :title="item.title">
      </title-component>
    </div>
  `,
  
  data: {
    items: [
      { title: 'Heading One' },
      { title: 'Heading Two' },
      { title: 'Heading Three' },
    ],
  },
}).$mount('#app');

.active {
  color: blue;
}

<!DOCTYPE html>
<html>
<head>
  <meta charset="utf-8">
  <meta name="viewport" content="width=device-width">
  <title></title>
</head>
<body>
  <div id="app"></div>
  <script src="https://cdnjs.cloudflare.com/ajax/libs/vue/2.0.3/vue.js"></script>
</body>
</html>

This example illustrates a solution to a particular issue. Key points covered are as follows:

Within v-for loops, the parent scope properties can be fully accessed. The v-for directive also allows for an optional second argument to access the index of the current item.

For more information refer to: https://v2.vuejs.org/v2/guide/list.html#Basic-Usage

The v-for directive provides a second argument that gives you the index of the current item.

v-for="(item, index) in items"

In this case, to apply the active class to the first item, utilize an expression to check if the index is equal to 0 and bind it to the class attribute.

:class="{ 'active': index === 0 }"

Answer 2

const TitleComponent = {
  template: `
    <h1>{{ title }}</h1>
  `,
  
  props: ['title'],
};

new Vue({
  components: {
    TitleComponent,
  },
  
  template: `
    <div>
      <title-component
        v-for="(item, index) in items"
        :class="{ 'active': index === 0 }"
        :title="item.title">
      </title-component>
    </div>
  `,
  
  data: {
    items: [
      { title: 'Heading One' },
      { title: 'Heading Two' },
      { title: 'Heading Three' },
    ],
  },
}).$mount('#app');

.active {
  color: blue;
}

<!DOCTYPE html>
<html>
<head>
  <meta charset="utf-8">
  <meta name="viewport" content="width=device-width">
  <title></title>
</head>
<body>
  <div id="app"></div>
  <script src="https://cdnjs.cloudflare.com/ajax/libs/vue/2.0.3/vue.js"></script>
</body>
</html>

This example illustrates a solution to a particular issue. Key points covered are as follows:

Within v-for loops, the parent scope properties can be fully accessed. The v-for directive also allows for an optional second argument to access the index of the current item.

For more information refer to: https://v2.vuejs.org/v2/guide/list.html#Basic-Usage

The v-for directive provides a second argument that gives you the index of the current item.

v-for="(item, index) in items"

In this case, to apply the active class to the first item, utilize an expression to check if the index is equal to 0 and bind it to the class attribute.

:class="{ 'active': index === 0 }"

Answer 3

Answer №2

To simplify the process, you can iterate through each element and check if the index is 0 before applying the active class (or any other desired class). Below is an example of how to define this class:

:class="{ 'active': index === 0 }"

Here is a practical demonstration using Bootstrap Tabs:

<ul class="nav nav-tabs tab-nav-right" role="tablist">
    <li role="presentation" :class="{ 'active': index === 0 }" v-for="(value, index) in some_array" v-bind:key="index">
        {{some_array[index]}}
    </li>
</ul>

If you need to apply multiple classes simultaneously, you can combine them as shown below:

:class="['tab-pane fade', (index === 0 ? 'active in' : 'something_else')]"

Answer 4

To simplify the process, you can iterate through each element and check if the index is 0 before applying the active class (or any other desired class). Below is an example of how to define this class:

:class="{ 'active': index === 0 }"

Here is a practical demonstration using Bootstrap Tabs:

<ul class="nav nav-tabs tab-nav-right" role="tablist">
    <li role="presentation" :class="{ 'active': index === 0 }" v-for="(value, index) in some_array" v-bind:key="index">
        {{some_array[index]}}
    </li>
</ul>

If you need to apply multiple classes simultaneously, you can combine them as shown below:

:class="['tab-pane fade', (index === 0 ? 'active in' : 'something_else')]"

Answer 5

Answer №3

To add an active class to the first element in a loop, you can programmatically control the class using VueJS.

VueJS allows you to bind the class of an anchor tag (or any other element like an li tag) directly to the index of the element, so that when the VueJS variable linked to the index changes, the class also changes. For more details, refer to the following links:

This is the key solution:

:class="{current:i == current}

You can find a working example on this fiddle link and another blog post explaining how to dynamically control the class of an li element in VueJS:

https://jsfiddle.net/Herteby/kpkcfcdw/

Answer 6

To add an active class to the first element in a loop, you can programmatically control the class using VueJS.

VueJS allows you to bind the class of an anchor tag (or any other element like an li tag) directly to the index of the element, so that when the VueJS variable linked to the index changes, the class also changes. For more details, refer to the following links:

This is the key solution:

:class="{current:i == current}

You can find a working example on this fiddle link and another blog post explaining how to dynamically control the class of an li element in VueJS:

https://jsfiddle.net/Herteby/kpkcfcdw/

Ways to add the class "active" to the initial element in a Vue.js for loop

Answer №1

Answer №2

Answer №3

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