Vue.js is a popular JavaScript framework that utilizes a powerful templating language, which is an extension of HTML. In addition to standard HTML, Vue.js introduces two essential features: interpolation and directives. Understanding these features is crucial for building dynamic and responsive Vue.js applications.

A Valid Vue.js Template To begin, it’s important to note that any HTML code is a valid Vue.js template. You can define a Vue component by explicitly declaring a template, like this:

new Vue({
 template: '<span>Hello!</span>'
})

Alternatively, you can leverage Single File Components, which store templates within separate files and are commonly used for larger applications:

<template>
 <span>Hello!</span>
</template>

Using Interpolation to Display Dynamic Data Vue.js allows you to display dynamic data by using interpolation. To start, you’ll need to add some data to your Vue component:

new Vue({
 data: {
 name: 'Flavio'
 },
 template: '<span>Hello!</span>'
})

Then, you can include the data in your template using the double brackets syntax:

new Vue({
 data: {
 name: 'Flavio'
 },
 template: '<span>Hello {{name}}!</span>'
})

Notice that we use name instead of this.data.name. Vue.js internally binds the template to the component’s properties, allowing for convenient access to data. This feature is particularly useful in Single File Components, where you can write:

<template>
 <span>Hello {{name}}!</span>
</template>

<script>
export default {
 data() {
 return {
 name: 'Flavio'
 }
 }
}
</script>

Interpolation with Flexibility While Vue.js interpolation shares similarities with Mustache or Handlebars template engines, it offers more flexibility. You can include any JavaScript expression within interpolations, as long as it is a single expression. For example:

{{ name.reverse() }}

{{ name === 'Flavio' ? 'Flavio' : 'stranger' }}

Additionally, Vue.js provides access to global objects like Math and Date for use in templates:

{{ Math.sqrt(16) * Math.random() }}

Using Templates Effectively It is best practice to avoid adding complex logic directly to templates. However, Vue.js allows it, which offers developers more flexibility, especially during experimentation phases. When working with complex expressions, it is recommended to start with the template and then migrate the logic to computed properties or methods to improve maintainability.

Reactivity and Escaping By default, any value included within an interpolation is updated automatically whenever the associated data properties change. However, you can opt out of this reactivity by using the v-once directive. It is important to note that the result of an interpolation is always escaped, meaning that HTML code will be treated as plain text.

Including HTML Snippets If you need to include HTML code within the output, you can utilize the v-html directive. This tells Vue.js to render the content as HTML instead of as plain text.

In conclusion, Vue.js templates and interpolations are powerful tools for creating dynamic and responsive applications. By understanding how to use interpolation and directives effectively, developers can build robust and flexible Vue.js applications.