How to understand conditional rendering in Vue.js? (code example)

In this tutorial, we will learn to understand conditional rendering in Vue.js.

What is conditional rendering?

Conditional rendering means that if a certain condition is true, then from Add or remove elements from dom.

In Vue, we need to use the v-if directive to render elements conditionally.

Let’s see an example:

<template>
  <div>
  <!-- v-if="javascript expression" -->
   <h1 v-if="isActive">Hello Vuejs</h1>
   <button @click="isActive= !isActive">点击</button>
  </div>
</template>

<script>

export default{
    data:function(){
        return{
            isActive:false
        }
    }
}
</script>

In the above code, we have added a v-if directive with the attribute isActive , so if the isActive attribute is true, the h1 element is only rendered into dom.

We can also extend the v-else directive after the v-if directive.

 <h1 v-if="isActive">Hello Vuejs</h1>
   <h1 v-else>Hey Vuejs</h1>

If the isActive attribute is true, the first h1 element will be rendered, otherwise the second h1 element will be # rendered ##dom中.

We can also extend this further using the

v-else-if block.

<h1 v-if="isActive">Hello Vuejs</h1>
   <h1 v-else-if="isActive && a.length===0">You&#39;re vuejs</h1>
   <h1 v-else>Hey Vuejs</h1>

In

JavaScript, the v-else-if directive works similarly to the else-if block.

Note: A

v-else element must be immediately followed by a v-if element or a v-if-else element, otherwise it will not work Identify it.

How to render multiple elements conditionally?

Sometimes we have to render multiple elements conditionally, in this case we need to combine the elements in Together.

<template>
  <div v-if="available">
    <h1>Items are available</h1>
    <p>More items in the stock</p>
  </div>
  <div v-else>
    <h1>Items are not available</h1>
    <p>Out of stock</p>
  </div>
</template>

<script>
export default {
  data: function() {
    return {
      available: true
    };
  }
};
</script>

Here we group multiple elements in

div tags.

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