Toggling Visibility with v-show
Hello, students! Welcome to Lesson 4 of Vue.js Directives. Today, we will learn about the v-show
directive and how to use it to toggle the visibility of elements.
What is the v-show Directive?
The v-show
directive allows toggling the visibility of an element. It is similar to the v-if
directive, but with an important difference: the v-show
directive does not remove the element from the DOM; it only changes its visibility.
How to Use the v-show Directive?
The basic syntax of the v-show
directive is as follows:
<element v-show="condition">
Where:
element
is the element whose visibility you want to toggle.condition
is a JavaScript expression that determines whether the element will be visible.
Example
Let’s see an example of how to use the v-show
directive to toggle the visibility of an element:
<div v-show="isLoggedIn"> <h1>Hello, user!</h1> </div>
In the example above, the div
element will be visible only if the isLoggedIn
property is true.
Other Examples
Let’s see some other examples of how to use the v-show
directive:
- Changing the visibility of an element only if the value of a property is greater than a certain value:
<div v-show="age > 18"> <h1>You are of legal age.</h1> </div>
- Changing the visibility of an element only if the user selects an option from a menu:
<div v-show="option === 'option 1'"> <h1>You selected option 1.</h1> </div>
JavaScript Expressions in the v-show Directive
You can use JavaScript expressions in the v-show
directive to determine whether the element will be visible.
For example, let’s see an example of how to use the v-show
directive to change the visibility of an element only if the current time value is greater than 12:
<div v-show="new Date().getHours() > 12"> <h1>Good afternoon!</h1> </div>
In the example above, the div
element will be visible only if the current time value is greater than 12.
Advantages of the v-show Directive over the v-if Directive
The v-show
directive has some advantages over the v-if
directive:
- The
v-show
directive does not remove the element from the DOM; it only changes its visibility. This can improve your application’s performance. - The
v-show
directive can be used to toggle the visibility of an element dynamically without needing to recreate the DOM.
Conclusion
The v-show
directive is a useful tool that can be used to toggle the visibility of elements. It is a good alternative to the v-if
directive in some cases.
Challenge
Here’s a challenge for you:
- Create a Vue.js application that displays a “like” button. The button should be visible only if the user is logged in.
Good luck!
Tip
You can use the v-show
directive to create a modal that is only displayed when the user clicks a button.