Implicit cross-mixin communication: multiple mixins that need to interact with one another have to rely on shared property keys, making them implicitly coupled. With composables, you can rename the destructured variables if there are conflicting keys from different composables. Namespace collisions: multiple mixins from different authors can potentially register the same property keys, causing namespace collisions. This is also why we recommend using the refs + destructure pattern for composables: it makes the property source clear in consuming components.

Unclear source of properties: when using many mixins, it becomes unclear which instance property is injected by which mixin, making it difficult to trace the implementation and understand the component's behavior. There are three primary drawbacks to mixins: Users coming from Vue 2 may be familiar with the mixins option, which also allows us to extract component logic into reusable units. Js // fetch.js import Comparisons with Other Techniques vs. If we were to implement the mouse tracking functionality using the Composition API directly inside a component, it would look like this: In real-world scenarios, it could also be more complex logic such as touch gestures or connection status to a database.

A simple example would be tracking the current position of the mouse on a page. There are many libraries out there for reusing stateless logic - for example lodash and date-fns, which you may have heard of.īy contrast, stateful logic involves managing state that changes over time. This formatter function encapsulates stateless logic: it takes some input and immediately returns expected output. For example, we may need to format dates in many places, so we extract a reusable function for that. When building frontend applications, we often need to reuse logic for common tasks. In the context of Vue applications, a 'composable' is a function that leverages Vue's Composition API to encapsulate and reuse stateful logic. If you have been learning Vue with Options API only, you can set the API Preference to Composition API (using the toggle at the top of the left sidebar) and re-read the Reactivity Fundamentals and Lifecycle Hooks chapters. This section assumes basic knowledge of Composition API.

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