Vue.js

Vue is a progressive framework for building user interfaces. Vue 3.5 (2025) solidifies the Composition API and introduces "Vapor Mode" for solid-js like performance.

When to Use

Progressive Adoption: Drop it into an existing HTML page or build a full SPA.
Developer Experience: Often cited as having the best balance of simplicity and power.
Performance: With Vapor Mode, it rivals the fastest signals-based frameworks.

Quick Start (Composition API)

<script setup>
import { ref, computed } from "vue";

const count = ref(0);
const double = computed(() => count.value * 2);

function increment() {
  count.value++;
}
</script>

<template>
  <button @click="increment">
    Count is: {{ count }}, Double is: {{ double }}
  </button>
</template>

Core Concepts

Composition API (`<script setup>`)

The standard way to write Vue components. It groups logic by feature, not by option type (data, methods, mounted).

Reactivity System (Signals)

Vue's reactivity is based on proxies. ref() and reactive() allow fine-grained dependency tracking.

Vapor Mode (Opt-in)

A compilation strategy that compiles Vue components into highly efficient JavaScript that modifies the DOM directly (no Virtual DOM).

Best Practices (2025)

Do:

Use <script setup>: It is less verbose and provides better TypeScript support.
Use defineModel: The new standard for two-way binding props (Vue 3.4+).
Use Composables: Extract logic into reusable useFeature() functions (Vue's version of Hooks).

Don't:

Don't mix Options and Composition API: Stick to Composition API for new projects.
Don't destructure props: You lose reactivity (unless using toRefs or Vue 3.5 reactive destructuring).

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