Discovering Vue 3: Insights and Best Practices for Developers
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Chapter 1: Understanding Vue 3's Reactive System
In the realm of Vue 3, understanding the reactivity system is crucial for effective development. One common question that arises is why ref is often preferred over reactive.
Reactiveness has its limitations. For instance, it is restricted to object types such as arrays and collections like Map and Set. It cannot accommodate primitive types like strings, numbers, or booleans. Furthermore, replacing a reactive object is not straightforward. Since Vue tracks reactivity through property access, maintaining the same reference to the reactive object is essential. This limitation hinders easy replacement, potentially breaking the reactive connection. Additionally, reactive objects are not ideal for deconstructive operations. When you extract primitive type properties from a reactive object or pass them into a function, you may lose their reactive nature.
Section 1.1: Ref Unwrapping
When it comes to template rendering, only the top-level ref properties are unwrapped. Unlike reactive objects, accessing a ref as an item in a reactive array or a native collection type (like Map) will not result in unwrapping.
Subsection 1.1.1: Timing Issues with watchPostEffect
By default, user-created listener callbacks are executed before Vue updates the component. This means that if you try to access the DOM within the listener, it will reflect the state prior to Vue's update. To access the DOM after Vue's update, you must use the flush: 'post' option.
watchEffect(
(onCleanup) => {
console.log(document.getElementById('pel'));
console.log('WatchEffect: Count changed:', state.count);
onCleanup(() => {
console.log('WatchEffect: onCleanup');});
},
{
flush: 'pre',},
);
Through experimentation, it's clear that using 'pre' can lead to null values when fetching the DOM for the first time, while 'post' successfully retrieves the DOM.
Return Value of watchEffect:
Both watchEffect and watch return a stop function that halts the listener when executed.
Section 1.2: Parsing Native HTML as Vue Components
Certain HTML elements impose restrictions on the types of elements that can be nested within them. For instance, components placed in invalid contexts can lead to errors in the final output.
To circumvent this, the special is attribute can be utilized. When applied to native HTML elements, the value of 'is' should start with 'vue:' to ensure it is interpreted as a Vue component.
Chapter 2: Exploring DefineProps and Macro Declarations
The first video titled "Vue 3 All-in-One Tutorial Series (3 Hours!)" offers an extensive overview of Vue 3, covering various features and best practices.
Macro declarations, such as defineProps, serve a unique purpose in Vue 3. They facilitate the declaration of attributes in child components and convert these attributes into reactive data. This transformation occurs during the compilation phase, allowing Vue to automatically track changes at runtime.
Section 2.1: The Role of v-bind
If you want to pass all properties of an object as props, you can use v-bind without specifying an argument. For example:
const post = { id: 1, title: 'My Journey with Vue' }
This is equivalent to using v-bind:prop-name.
Section 2.2: Understanding onMounted Synchronization
When onMounted is called, Vue registers the callback function on the currently initializing component instance. This registration occurs synchronously, so avoid wrapping onMounted calls in asynchronous functions like setTimeout.
Section 2.3: Asynchronous Components and Suspense
The second video, "The Ultimate Vue 3 Tutorial (100% Composition API)," delves into the use of asynchronous components and the Suspense feature.
Suspense recognizes components with asynchronous dependencies, waiting for them to finish before rendering. The events triggered during this process include 'pending', 'fallback', and 'resolve'. If no dependencies are detected during initial rendering, Suspense will complete without entering a suspended state.
Timeout in Suspense:
The timeout prop controls how quickly the fallback content is displayed when the primary content is delayed. If set to zero, the fallback content appears immediately upon replacement.
Chapter 3: Implementing Custom Components and Attributes
To implement v-model with custom components, you can define reactive properties and emit changes effectively.
Custom modifiers, such as modelModifiers, allow for additional logical handling based on the presence of specific properties.
Attribute penetration refers to the ability of attributes not declared as props to be passed through to the root element of a component. From Vue 3.3 onwards, you can use defineOptions to manage attribute inheritance.
In summary, this guide provides a detailed exploration of Vue 3 features, best practices, and nuances, ensuring that developers can harness the full potential of this powerful framework. Thank you for joining me on this journey through Vue 3. Please consider giving feedback and following for more insights!