Is a DOM lookup performed each time Vue's ref is utilized?

Question

Is a DOM lookup performed each time Vue's ref is utilized?

Exploring the capabilities of Vue.js, I have integrated a few refs into my current project. However, I am curious about the efficiency of calling refs in methods. Does Vue perform a DOM lookup every time a ref is called, or does it store all refs once for easy access?

Despite extensive research through documentation and Google searches, I have yet to find a definitive answer.

https://v2.vuejs.org/v2/api/#ref

For instance:

myDiv = this.$refs.myDiv

Should I manually save the ref in a variable, or is there no performance impact when repeatedly calling the same ref?

javascript performance vue.js

Answer 1

Answer №1

Upon initialization of a vue instance, the source code reveals that it assigns the property $ref = { } to an empty object. Refer to the initLifecycle function

The vm.$refs object is filled by verifying if the virtual node contains a ref attribute, specifically vnode.data.ref in the registerRef function.

Hence, manual intervention in this process is unnecessary.

It's important to note that referencing $refs.myRef does not entail a direct DOM search; instead, it is handled by the virtual dom patch mechanism.

Answer 2

Upon initialization of a vue instance, the source code reveals that it assigns the property $ref = { } to an empty object. Refer to the initLifecycle function

The vm.$refs object is filled by verifying if the virtual node contains a ref attribute, specifically vnode.data.ref in the registerRef function.

Hence, manual intervention in this process is unnecessary.

It's important to note that referencing $refs.myRef does not entail a direct DOM search; instead, it is handled by the virtual dom patch mechanism.

Answer 3

Answer №2

Does the ref attribute in Vue require a DOM lookup each time it is accessed?

The simple answer is No.

Here's my basic understanding: (Feel free to correct me if I am mistaken)

Vue utilizes a virtual DOM. In Vue, a virtual representation of the actual DOM is known as a VNode. Vue first creates a VNode based on templates and scripts. Subsequently, Vue compares the virtual DOM (the tree consisting of all the VNodes) with the real DOM. If there are variations between the real and virtual DOM, Vue generates the DOM element using document.createElement (or similar DOM creation method). The result of document.createElement is a reference to the tangible DOM element. This reference is stored in Vnode.elm before being appended to the display. Whenever a VNode is produced/updated/destroyed, Vue examines the ref attribute and designates this.$refs.refname as equal to Vnode.elm.

In essence, there is no need for a repetitive DOM lookup. The VNode already contains the pointer to the real DOM element. When utilizing ref, Vue simply assigns the existing DOM pointer to the $refs

Answer 4

Does the ref attribute in Vue require a DOM lookup each time it is accessed?

The simple answer is No.

Here's my basic understanding: (Feel free to correct me if I am mistaken)

Vue utilizes a virtual DOM. In Vue, a virtual representation of the actual DOM is known as a VNode. Vue first creates a VNode based on templates and scripts. Subsequently, Vue compares the virtual DOM (the tree consisting of all the VNodes) with the real DOM. If there are variations between the real and virtual DOM, Vue generates the DOM element using document.createElement (or similar DOM creation method). The result of document.createElement is a reference to the tangible DOM element. This reference is stored in Vnode.elm before being appended to the display. Whenever a VNode is produced/updated/destroyed, Vue examines the ref attribute and designates this.$refs.refname as equal to Vnode.elm.

In essence, there is no need for a repetitive DOM lookup. The VNode already contains the pointer to the real DOM element. When utilizing ref, Vue simply assigns the existing DOM pointer to the $refs

Answer 5

Answer №3

Stored in the object $refs, the references are only registered once and can be accessed directly without any issues.

Answer 6

Stored in the object $refs, the references are only registered once and can be accessed directly without any issues.

Is a DOM lookup performed each time Vue's ref is utilized?

Answer №1

Answer №2

Answer №3

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