Vue when are refs available?

In this tutorial, we’ll demonstrate how to reference HTML elements in your Vue.js components.

We’ll cover the following in detail:

This Vue refs tutorial is suited for all stages of developers who use Vue — including beginners. Here are a few prerequisites before you get started:

Vue.js is a progressive JavaScript framework created by Evan You and the Vue core team with contributions from more than 230 community members. Vue is used in more than 870,000 projects and has more than 175,000 stars on GitHub.

Vue.js is an approachable core library that focuses only on the view layer. It also has a massive ecosystem of supporting libraries that help you easily build responsive web experiences.

Refs are Vue.js instance properties that are used to register or indicate a reference to HTML elements or child elements in the template of your application.

If a ref attribute is added to an HTML element in your Vue template, you’ll then be able to reference that element or even a child element in your Vue instance. You can also access the DOM element directly; it is a read-only attribute and returns an object.

The use of JavaScript’s getElementById is not encouraged in Vue, as it creates performance issues. Vue’s ref helps you “reference” DOM elements in a more efficient way.

The ref attribute makes a DOM element selectable by serving as the key in the parent $ref attribute.

Putting a ref attribute in an input element, for instance, will expose the parent DOM node as this.$refs.input, or you can say this.refs["input"].

For a quick visual guide on referencing with $refs in Vue.js, check out this video tutorial.

You can manipulate a DOM element by defining methods on the element’s reference. For example, you could focus on an input element with this:

In this way, refs can be used just like the document.querySelector('.element') in JavaScript or the $('.element') in jQuery. While document.querySelector() performs some of the functions of refs, refs are more efficient, because they give you direct access to the specific element you need. On the other hand, document.querySelector() simply returns the first element in your DOM that matches the selector you specified. The $refs can be accessed both inside the Vue.js instance and outside of it. However, they are not data properties, so they are not reactive.

On template inspection in your browser, $refs do not show up at all because it is not an HTML attribute; it is only a Vue template attribute.

If you followed this post from the start, you should have downloaded the starter project and opened it up on VS Code. Open the components folder and copy this into the test.vue file:

Now run this in your development server with the command:

You will see that the user interface displays a simple counter that gets updated on click, but when you open your developer tools in the browser, you will notice that it logs undefined.

It is very important that you get the syntax right because this means that Vue does not see this as an error, but it is. According to what we already know about Vue refs, they return an object, but judging by the undefined response, something is wrong.

Copy the code below into the test.vue file:

When you run this and inspect it, you will notice that it now returns an object:

A quick look at the code block will reveal the correct syntax: inside the template, it is called ref, but when we refer to it in the Vue instance, it is called $refs. This is very important to note to not get an undefined returned. The syntax ref that’s used inside the template is an attribute given to an element. $refs on the other hand, is a collection of the elements in your application that have been given the ref attribute. You can access every single possible property of the referenced element, including the element as it is in the template.

Let’s try logging some of the properties that might be of interest to us. Your test.vue file should be:

The application on your browser should look like this:

To display the HTML element as it is in the DOM, go into the submit method and change the methods code to the following:

The input here is the reference name you created earlier inside the element (ref="input"). It can be any name of your choice.

To display the HTML element input value — the string that was typed into the text box in the user interface — go into the submit method and change the code to:

This displays exactly the string you type in, which shows a similarity to query selection which vanilla JavaScript and jQuery can achieve too.

The webpage in which the element can be found is also one of the many things that can be displayed with the Vue ref. Go into the submit method and change the code to this:

There are many other things you can both access and log with the ref just from information on the returned object.

Vue.js refs can also be used inside elements that output more than one element in the DOM, like conditional statements where v-for directives are used. Instead of objects, refs return an array of the items when called. To illustrate this, create a simple list like this:

When you run it again in the development server, it will look like this:

Say you want to react to a change in a DOM element, like triggering a function when the value of an element changes. You can set up a watcher for this.

Below, we have a simple component with data:

We create the watcher inside the mounted hook so that it only takes effect after the component has been rendered. We use the $watch() instance method to watch for changes in the component’s data, myName. When the value changes, the console.log function is triggered.

You can find the full code of this tutorial on GitHub.

This post has exposed you to referencing HTML elements in your DOM in Vue.js. You can now both access and log these elements by all the element properties, including value, child node, data attributes, and even the base URL that houses it.

You have also been introduced to ways you can achieve this. It is important to note that refs get populated after the Vue instance has initialized and the component has been rendered, so using refs in computed properties is discouraged because it has the ability to directly manipulate child nodes. Happy hacking!

Note that you can only access the ref after the component is mounted. If you try to access $refs.input in a template expression, it will be null on the first render. This is because the element doesn't exist until after the first render!

You'd still need to also avoid wrapping your component with v-if and use this.$refs.mapRef in mounted(), instead of created()

I wasn't using Vue Google Maps plugin/component, but my own custom component

Use:

Instead of

Use this.$refs.mapRef in mounted() instead of created().

This way, setTimeout() and this.$nextTick() not needed

Correct way:

Wrong way:

Do not wrap child component using v-if, use v-show instead.

Correct way:

Wrong way:

The following are methods I tried but didn't work until I used the methods on top (stopped using dynamic import)

I already put this.$refs.mapRef in mounted() tried to wrap it with setTimeout() and 2 layers of this.$nextTick().