In Vue.js, you can create computed properties by using the computed option. Computed properties are functions that are defined in the computed object and return a value based on the reactive data properties in your Vue instance.
Here's an example of how to create computed properties in Vue.js:
<div id="app">
<p>Original value: {{ message }}</p>
<p>Computed reversed value: {{ reversedMessage }}</p>
<button @click="reverseMessage">Reverse</button>
</div>
new Vue({
el: '#app',
data: {
message: 'Hello Vue.js!'
},
computed: {
reversedMessage: function() {
return this.message.split('').reverse().join('');
}
},
methods: {
reverseMessage: function() {
this.message = this.message.split('').reverse().join('');
}
}
});
In this example, the reversedMessage computed property returns the reversed value of the message data property. Whenever the message changes, the reversedMessage will be automatically updated.
Note that computed properties are cached based on their reactive dependencies. This means that if you access the computed property multiple times, it will only be recomputed if its dependencies have changed.