How to use $refs to access components and HTML elements in Vue

$refs in Vue is a very convenient feature that allows us to access components and HTML elements in a Vue instance. This feature allows us to directly access DOM elements in templates, calculated properties, methods and life cycle hooks, and can simplify code writing. This article will introduce how to use $refs to access components and HTML elements in Vue.

1. Access components

In Vue, components are important modules. We will use many components in the project, so access to components is very necessary. So, how can we use $refs to access components?

In Vue, we can set a ref attribute for the component. In templates or JS, we can use $refs to access this component.

Let’s write an example:

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<child-component ref="myComponent"></child-component>

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import ChildComponent from './ChildComponent.vue'

export default {
components: {

ChildComponent

},
mounted () {

this.$refs.myComponent.doSomething()

}
}
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In this example, we reference a child component named ChildComponent in the parent component, and Added a ref attribute for access. In the mounted life cycle hook, we can access this component and call the doSomething method of this component.

In short, it is very convenient to use $refs to access components, and we can use it directly for access operations.

2. Accessing HTML elements

It is also very simple to use $refs to access HTML elements. We can also set a ref attribute for an element and then use $refs to access this element in JS. Let’s write an example:

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<input type="text" ref="myInput">

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< ;script>
export default {
mounted() {

this.$refs.myInput.focus()

}
}
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In this example, we give input The element adds a ref attribute for access. In the mounted lifecycle hook, we call the focus() method to make the input element the focus.

Similarly, it is also very convenient to use $refs to access HTML elements. We can directly add the ref attribute to the element in the template to perform access operations.

3. Things to note

In Vue, it is very convenient to use $refs to access components and HTML elements, but it must be used with caution. The components and elements accessed by $refs must have been rendered. If you access an element or component before mounting it, you will get undefined.

In a Vue component, if we perform asynchronous operations or manipulate data, the component's life cycle hook will change. This change may cause $refs to return undefined. Therefore, be careful when using $refs and make sure that when accessing an element or component it has been rendered.

At the same time, we also need to pay attention to the naming of components to ensure their uniqueness. Because when a component is accessed through $refs, it is accessed by name. If there are multiple components with the same name, incorrect components may be accessed.

4. Summary

In Vue, it is very convenient to use $refs to access components and HTML elements. Just add a ref attribute to the component or element and you can access it in JS. However, we need to be careful that the component or element returned by $refs has already been rendered, and we need to pay attention to the naming of the component to ensure its uniqueness.

In actual development, we can use $refs in conjunction with v-if, v-for and other instructions to help us complete the project better. Of course, when using $refs, be sure not to overuse it, and avoid directly modifying the data in the child component in the parent component, which will destroy the principle of one-way data flow.

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