Svelte 3: A Fresh Approach to Front-End Development
This article explores Svelte 3, a unique front-end JavaScript framework that distinguishes itself through its compilation process. Unlike frameworks like React, which ship a large JavaScript bundle, Svelte compiles applications into significantly smaller, optimized JavaScript code. This optimization, achieved during the build process, results in faster and more efficient applications.
Svelte also offers a distinctive approach to data management and DOM manipulation. It directly updates the real DOM, eliminating the need for a virtual DOM, leading to improved performance. This, coupled with its intuitive component creation and built-in reactive states, makes development enjoyable and efficient. Even seasoned React or Vue developers will find Svelte worth exploring. Let's build a simple application to demonstrate its capabilities.
Key Advantages of Svelte:
- Optimized JavaScript: Svelte compiles to optimized JavaScript, reducing runtime size compared to frameworks like React.
- Direct DOM Manipulation: Svelte updates the real DOM directly, enhancing data management and DOM manipulation efficiency.
- Simplified Components: Component creation is streamlined with scoped CSS and integrated reactive states.
- Less Boilerplate: The compiler approach minimizes code and boilerplate, accelerating development.
- Intuitive Syntax: Reactivity and component communication are handled with minimal syntax.
- Lightweight and Efficient: Svelte offers a lightweight alternative to heavier frameworks like React and Vue.
Getting Started:
To avoid complexities of bundling and infrastructure, we'll follow the official Svelte tutorial. Ensure you have Node and Git installed. Then, execute:
npx degit sveltejs/template github-repository-searcher
This clones the Svelte template into the github-repository-searcher
directory and sets up the necessary tooling. Afterward, navigate to the directory (cd github-repository-searcher
) and run npm install
to install dependencies. Finally, npm run dev
starts the development server using Rollup. Access the application at http://localhost:5000
.
Building a Svelte Component:
Svelte components reside in .svelte
files. The template provides App.svelte
, structured into three sections:
<code></li> <style> /* CSS for styling the list */ </style> <div class="search-wrapper"> <form class="search-form"> <input type="text" bind:value={userSearchTerm} placeholder="search for repositories" /> </form> <ul> {#each filteredRepos as repository} <li> <strong>{repository.name}</strong> <code>{repository.url}
<style> /* CSS for styling the list */{#each filteredRepos as repository}{repository.name}{repository.url}<p> <code>Search
{/each}App.svelte
repositories
Import
Svelte's reactivity is demonstrated by theSearch</strong> into <code>App.svelte</p> and use it conditionally based on the availability of <code>repositories<p>.<code>$:
Search.svelte
filteredRepos
Reactivity and Filtering:userSearchTerm
repositories
$:<p> syntax in <code>Search.svelte<strong>. This ensures <code>filteredRepos</strong> updates whenever <code>userSearchTerm</p> or <code>repositories<p> changes. Alternative approaches using functions or event listeners are also discussed, highlighting the benefits of Svelte's reactivity features.<code>npm run build
Production Build:
Runnpm run build<p> to create a production-ready bundle. The resulting bundle size is typically small due to Svelte's compilation process.</p> <p><strong>Conclusion:</strong></p> <ul>Svelte offers a compelling alternative to traditional frameworks, emphasizing code efficiency and performance. Its intuitive syntax and built-in features simplify development, making it a strong contender for front-end development.<li> <strong></strong>Svelte FAQ (Concise Version):</li><li> <strong> </strong></li>What is Svelte?<li> A JavaScript framework compiling to optimized code, shifting work from runtime to build time.<strong> </strong></li>How does Svelte differ from React/Vue?<li> Svelte compiles to smaller, faster code; React/Vue do more work in the browser.<strong> </strong></li>How does Svelte handle components?<li> Components are written in an HTML/CSS/JS-like syntax and compiled to efficient JavaScript.<strong> </strong></li>Does Svelte use a virtual DOM?<li> No, it updates the real DOM directly.<strong> </strong></li>What is SvelteKit?</ul> A higher-level framework for building complete web applications on top of Svelte.<p> <img src="/static/imghw/default1.png" data-src="https://img.php.cn/upload/article/000/000/000/173932009210437.jpg" class="lazy" alt="Svelte 3: A Radical Compiler-based JavaScript Framework" /></p>Advantages of Svelte?<script>
: Contains JavaScript logic.<style>
: Houses scoped CSS (styles are confined to the component).- HTML: Forms the component's output, incorporating Svelte's templating features.
To ensure efficient editing, install a Svelte extension for your code editor.
User Input and GitHub API Interaction:
Our application prompts the user for a GitHub username, then fetches their repositories using the GitHub API. We'll modify App.svelte
:
- Remove the
export let name
line from the<script>
section and updatesrc/main.js
to remove unnecessary props. - Add a form to collect the username:
<main> <form on:submit|preventDefault={onSubmit}> <label for="username">Enter a GitHub username:</label> <input type="text" name="username" placeholder="jackfranklin" bind:value={usernameInputField} /> <button type="submit">Load repositories</button> </form> {#if repositories} <Search repositories={repositories} /> {/if} </main>
- Add the following JavaScript to handle form submission and API interaction:
let usernameInputField = ""; let repositories = undefined; async function onSubmit() { const url = `https://api.github.com/users/${usernameInputField}/repos`; const response = await fetch(url); repositories = await response.json(); }
Creating and Using the Search Component:
Create Search.svelte
to display and filter repositories. This component accepts repositories
as a prop:
<code class="svelte"><script> export let repositories; let userSearchTerm = ""; $: filteredRepos = repositories.filter((repo) => repo.name.toLowerCase().includes(userSearchTerm.toLowerCase()) ); </script> Smaller bundle sizes, faster performance, simple syntax, less boilerplate. </code>
The above is the detailed content of Svelte 3: A Radical Compiler-based JavaScript Framework. For more information, please follow other related articles on the PHP Chinese website!

Hot AI Tools

Undress AI Tool
Undress images for free

Undresser.AI Undress
AI-powered app for creating realistic nude photos

AI Clothes Remover
Online AI tool for removing clothes from photos.

Clothoff.io
AI clothes remover

Video Face Swap
Swap faces in any video effortlessly with our completely free AI face swap tool!

Hot Article

Hot Tools

Notepad++7.3.1
Easy-to-use and free code editor

SublimeText3 Chinese version
Chinese version, very easy to use

Zend Studio 13.0.1
Powerful PHP integrated development environment

Dreamweaver CS6
Visual web development tools

SublimeText3 Mac version
God-level code editing software (SublimeText3)

There are three common ways to initiate HTTP requests in Node.js: use built-in modules, axios, and node-fetch. 1. Use the built-in http/https module without dependencies, which is suitable for basic scenarios, but requires manual processing of data stitching and error monitoring, such as using https.get() to obtain data or send POST requests through .write(); 2.axios is a third-party library based on Promise. It has concise syntax and powerful functions, supports async/await, automatic JSON conversion, interceptor, etc. It is recommended to simplify asynchronous request operations; 3.node-fetch provides a style similar to browser fetch, based on Promise and simple syntax

JavaScript data types are divided into primitive types and reference types. Primitive types include string, number, boolean, null, undefined, and symbol. The values are immutable and copies are copied when assigning values, so they do not affect each other; reference types such as objects, arrays and functions store memory addresses, and variables pointing to the same object will affect each other. Typeof and instanceof can be used to determine types, but pay attention to the historical issues of typeofnull. Understanding these two types of differences can help write more stable and reliable code.

Which JavaScript framework is the best choice? The answer is to choose the most suitable one according to your needs. 1.React is flexible and free, suitable for medium and large projects that require high customization and team architecture capabilities; 2. Angular provides complete solutions, suitable for enterprise-level applications and long-term maintenance; 3. Vue is easy to use, suitable for small and medium-sized projects or rapid development. In addition, whether there is an existing technology stack, team size, project life cycle and whether SSR is needed are also important factors in choosing a framework. In short, there is no absolutely the best framework, the best choice is the one that suits your needs.

Hello, JavaScript developers! Welcome to this week's JavaScript news! This week we will focus on: Oracle's trademark dispute with Deno, new JavaScript time objects are supported by browsers, Google Chrome updates, and some powerful developer tools. Let's get started! Oracle's trademark dispute with Deno Oracle's attempt to register a "JavaScript" trademark has caused controversy. Ryan Dahl, the creator of Node.js and Deno, has filed a petition to cancel the trademark, and he believes that JavaScript is an open standard and should not be used by Oracle

CacheAPI is a tool provided by the browser to cache network requests, which is often used in conjunction with ServiceWorker to improve website performance and offline experience. 1. It allows developers to manually store resources such as scripts, style sheets, pictures, etc.; 2. It can match cache responses according to requests; 3. It supports deleting specific caches or clearing the entire cache; 4. It can implement cache priority or network priority strategies through ServiceWorker listening to fetch events; 5. It is often used for offline support, speed up repeated access speed, preloading key resources and background update content; 6. When using it, you need to pay attention to cache version control, storage restrictions and the difference from HTTP caching mechanism.

Promise is the core mechanism for handling asynchronous operations in JavaScript. Understanding chain calls, error handling and combiners is the key to mastering their applications. 1. The chain call returns a new Promise through .then() to realize asynchronous process concatenation. Each .then() receives the previous result and can return a value or a Promise; 2. Error handling should use .catch() to catch exceptions to avoid silent failures, and can return the default value in catch to continue the process; 3. Combinators such as Promise.all() (successfully successful only after all success), Promise.race() (the first completion is returned) and Promise.allSettled() (waiting for all completions)

JavaScript array built-in methods such as .map(), .filter() and .reduce() can simplify data processing; 1) .map() is used to convert elements one to one to generate new arrays; 2) .filter() is used to filter elements by condition; 3) .reduce() is used to aggregate data as a single value; misuse should be avoided when used, resulting in side effects or performance problems.

JavaScript's event loop manages asynchronous operations by coordinating call stacks, WebAPIs, and task queues. 1. The call stack executes synchronous code, and when encountering asynchronous tasks, it is handed over to WebAPI for processing; 2. After the WebAPI completes the task in the background, it puts the callback into the corresponding queue (macro task or micro task); 3. The event loop checks whether the call stack is empty. If it is empty, the callback is taken out from the queue and pushed into the call stack for execution; 4. Micro tasks (such as Promise.then) take precedence over macro tasks (such as setTimeout); 5. Understanding the event loop helps to avoid blocking the main thread and optimize the code execution order.
