Understanding the value Property in Vue.js 3: ref vs reactive

Explore the differences between `ref` and `reactive` in Vue.js 3, and learn why you must use the `value` property with `ref`.
---
This video is based on the question https://stackoverflow.com/q/63437604/ asked by the user 'Golo Roden' ( https://stackoverflow.com/u/1333873/ ) and on the answer https://stackoverflow.com/a/63827806/ provided by the user 'Aito Hideki' ( https://stackoverflow.com/u/14245191/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

Visit these links for original content and any more details, such as alternate solutions, latest updates/developments on topic, comments, revision history etc. For example, the original title of the Question was: In Vue.js 3, why do I have to use the value property on ref, but not on reactive?

Also, Content (except music) licensed under CC BY-SA https://meta.stackexchange.com/help/l...
The original Question post is licensed under the 'CC BY-SA 4.0' ( https://creativecommons.org/licenses/... ) license, and the original Answer post is licensed under the 'CC BY-SA 4.0' ( https://creativecommons.org/licenses/... ) license.

If anything seems off to you, please feel free to write me at vlogize [AT] gmail [DOT] com.
---
Understanding the value Property in Vue.js 3: ref vs reactive

When working with Vue.js 3, particularly with the Composition API, you may encounter the terms ref and reactive. A common confusion arises: why do we need to use the value property with ref but not with reactive? This post aims to clarify this difference and provide insights into the underlying mechanics of Vue's reactivity system.

The Basics: What Are ref and reactive?

Both ref and reactive are tools in Vue.js designed to enable reactivity—allowing your application to efficiently keep track of changes and update the UI accordingly.

ref: This is intended for single, primitive values (like numbers, strings, or booleans).

reactive: This is made for more complex data structures, such as objects and arrays.

Example

Here’s a quick example demonstrating the use of ref and reactive:

[[See Video to Reveal this Text or Code Snippet]]

Why the value Property with ref?

The key difference lies in how Vue tracks changes to these two types of data:

ref is a wrapper that specifically keeps an eye on its value property. When that value changes, Vue triggers reactivity and updates any dependent components or properties.

In contrast, reactive monitors all its properties, making it unnecessary to reference a value property.

Comfort and Usability

Imagine if Vue only used reactive for both single and complex variables:

[[See Video to Reveal this Text or Code Snippet]]

This would mean that in your templates or scripts, you'd consistently have to reference refSingle.value, which would get cumbersome. Using ref allows you to access the value directly without any additional syntax.

Why Not Use One for Both?

You might wonder, why not have a single function that determines how to wrap a variable based on its type? Here are a couple of reasons:

Simplicity and Performance: The separation between ref and reactive keeps the reactivity system straightforward and efficient. Since Vue can directly optimize based on the type of variable, it enhances performance when updating the UI.

Reacting to Changes: While ref listens to its value, allowing a more straightforward syntax for single values, reactive must manage a more complex internal structure for objects. Mixing these could complicate reactivity at scale.

The Right Tool for the Right Job

If you need a single-valued reactive state, stick to ref:

[[See Video to Reveal this Text or Code Snippet]]

If you're dealing with objects or arrays, reactive is your best bet:

[[See Video to Reveal this Text or Code Snippet]]

Conclusion

Understanding when and why to use value with ref but not with reactive is crucial for leveraging Vue.js 3's reactivity efficiently. Both serve distinct purposes and work optimally when used in the right context. By keeping these concepts in mind, you can write cleaner, more effective Vue.js applications.

Now, you're equipped to make the best choices in your reactivity strategy! Happy coding!