大家好,我是老十三,一名前端开发工程师。在前端的江湖中,React与Vue如同两大武林门派,各有千秋。今天,我将带你进入这两大框架的奥秘世界,共同探索组件生命周期、状态管理、性能优化等核心难题的解决之道。无论你是哪派弟子,掌握双修之术,才能在前端之路上游刃有余。准备好启程了吗?
掌握了DOM渡劫的九道试炼后,是时候踏入现代前端的核心领域——框架修行。在这条充满挑战的双修之路上,我们将探索React与Vue这两大主流框架的精髓,以及它们背后的设计哲学。
🔄 第一难:生命周期 - 组件的"六道轮回"
问题:组件从创建到销毁经历了哪些阶段?如何在正确的生命周期阶段执行相应操作?
深度技术:
组件生命周期是前端框架的核心概念,描述了组件从创建、更新到销毁的完整过程。理解生命周期,意味着掌握了何时获取数据、何时操作DOM以及何时清理资源。
React和Vue在生命周期设计上既有相似之处,也有显著区别。React强调函数式理念,推动Hooks模式;Vue则提供更直观的选项式API,同时也支持组合式API。无论哪种方式,合理使用生命周期钩子都是构建高性能应用的关键。
代码示例:
// React Hooks生命周期
function HooksLifecycle() {
const [count, setCount] = React.useState(0);
const [userId, setUserId] = React.useState(1);
const prevUserIdRef = React.useRef();
// 相当于constructor + componentDidMount + componentDidUpdate
React.useEffect(() => {
console.log('组件挂载或更新');
// 设置定时器
const timer = setInterval(() => {
setCount(c => c + 1);
}, 1000);
// 返回清理函数,相当于componentWillUnmount
return () => {
console.log('组件卸载或更新前清理');
clearInterval(timer);
};
}, []); // 空依赖数组,仅在挂载和卸载时执行
// 监听特定依赖变化
React.useEffect(() => {
console.log('userId发生变化,获取新用户数据');
fetchUserData(userId);
}, [userId]); // 仅当userId变化时执行
// 模拟getDerivedStateFromProps
React.useEffect(() => {
if (prevUserIdRef.current !== userId) {
console.log('从props派生状态');
}
prevUserIdRef.current = userId;
});
// 模拟componentDidUpdate - 比较前后值
const prevCountRef = React.useRef();
React.useEffect(() => {
const prevCount = prevCountRef.current;
if (prevCount !== undefined && prevCount !== count) {
console.log('count从', prevCount, '变为', count);
}
prevCountRef.current = count;
});
// 使用布局效果,在DOM变更后同步触发
React.useLayoutEffect(() => {
console.log('DOM更新后立即执行,浏览器绘制前');
// 获取DOM测量或直接操作DOM
});
return (
<div>
<h1>Hooks计数器: {count}</h1>
<button onClick={() => setCount(count + 1)}>增加</button>
<button onClick={() => setUserId(userId + 1)}>切换用户</button>
</div>
);
}
// Vue 3组合式API生命周期
import { ref, onMounted, onBeforeMount, onUpdated, onBeforeUpdate, onBeforeUnmount, onUnmounted, watch } from 'vue';
const LifecycleDemo = {
setup() {
const count = ref(0);
const message = ref('Hello Vue 3');
onBeforeMount(() => {
console.log('1. onBeforeMount: 组件挂载前');
});
onMounted(() => {
console.log('2. onMounted: 组件已挂载');
// 适合进行DOM操作、网络请求、订阅事件
const timer = setInterval(() => {
count.value++;
}, 1000);
// 清理函数
onBeforeUnmount(() => {
clearInterval(timer);
});
});
onBeforeUpdate(() => {
console.log('3. onBeforeUpdate: 组件更新前');
});
onUpdated(() => {
console.log('4. onUpdated: 组件已更新');
});
onBeforeUnmount(() => {
console.log('5. onBeforeUnmount: 组件卸载前');
});
onUnmounted(() => {
console.log('6. onUnmounted: 组件已卸载');
});
// 监听数据变化
watch(count, (newValue, oldValue) => {
console.log(`count从${oldValue}变为${newValue}`);
});
return {
count,
message
};
}
};
🔄 第二难:状态管理 - 数据的"太极之道"
问题:如何优雅地管理应用状态?Redux和Vuex各有什么特点?
深度技术:
状态管理是前端应用的核心挑战之一。Redux遵循严格的单向数据流和不可变数据原则,强调纯函数reducer;Vuex则采用更贴近Vue的响应式设计。理解这两种范式的差异和适用场景,是框架修行的关键一步。
代码示例:
// Redux Toolkit示例
import {
createSlice, configureStore } from '@reduxjs/toolkit';
// 创建slice
const todoSlice = createSlice({
name: 'todos',
initialState: {
items: [],
filter: 'all'
},
reducers: {
addTodo: (state, action) => {
state.items.push({
id: Date.now(),
text: action.payload,
completed: false
});
},
toggleTodo: (state, action) => {
const todo = state.items.find(todo => todo.id === action.payload);
if (todo) {
todo.completed = !todo.completed;
}
},
setFilter: (state, action) => {
state.filter = action.payload;
}
}
});
// 导出actions
export const {
addTodo, toggleTodo, setFilter } = todoSlice.actions;
// 创建store
const store = configureStore({
reducer: {
todos: todoSlice.reducer
}
});
// React组件中使用Redux Toolkit
import {
useSelector, useDispatch } from 'react-redux';
function TodoApp() {
const dispatch = useDispatch();
const todos = useSelector(state => state.todos.items);
const filter = useSelector(state => state.todos.filter);
const [newTodo, setNewTodo] = React.useState('');
const handleSubmit = e => {
e.preventDefault();
if (!newTodo.trim()) return;
dispatch(addTodo(newTodo));
setNewTodo('');
};
return (
<div>
<h1>Todo应用</h1>
<form onSubmit={
handleSubmit}>
<input
value={
newTodo}
onChange={
e => setNewTodo(e.target.value)}
placeholder="添加新任务"
/>
<button type="submit">添加</button>
</form>
<div>
<button onClick={
() => dispatch(setFilter('all'))}>
全部
</button>
<button onClick={
() => dispatch(setFilter('active'))}>
进行中
</button>
<button onClick={
() => dispatch(setFilter('completed'))}>
已完成
</button>
<span>当前: {
filter}</span>
</div>
<ul>
{
todos.map(todo => (
<li
key={
todo.id}
style={
{
textDecoration: todo.completed ? 'line-through' : 'none' }}
onClick={
() => dispatch(toggleTodo(todo.id))}
>
{
todo.text}
</li>
))}
</ul>
</div>
);
}
// Pinia示例
import {
defineStore } from 'pinia';
export const useTodoStore = defineStore('todos', {
state: () => ({
items: [],
filter: 'all'
}),
getters: {
visibleTodos: (state) => {
switch (state.filter) {
case 'active':
return state.items.filter(todo => !todo.completed);
case 'completed':
return state.items.filter(todo => todo.completed);
default:
return state.items;
}
}
},
actions: {
addTodo(text) {
this.items.push({
id: Date.now(),
text,
completed: false
});
},
toggleTodo(id) {
const todo = this.items.find(todo => todo.id === id);
if (todo) {
todo.completed = !todo.completed;
}
},
setFilter(filter) {
this.filter = filter;
}
}
});
// Vue组件中使用Pinia
import {
useTodoStore } from './stores/todo';
const TodoApp = {
setup() {
const store = useTodoStore();
const newTodo = ref('');
const handleSubmit = () => {
if (!newTodo.value.trim()) return;
store.addTodo(newTodo.value);
newTodo.value = '';
};
return {
store,
newTodo,
handleSubmit
};
},
template: `
<div>
<h1>Todo应用</h1>
<form @submit.prevent="handleSubmit">
<input
v-model="newTodo"
placeholder="添加新任务"
/>
<button type="submit">添加</button>
</form>
<div>
<button @click="store.setFilter('all')">全部</button>
<button @click="store.setFilter('active')">进行中</button>
<button @click="store.setFilter('completed')">已完成</button>
<span>当前: {
{ store.filter }}</span>
</div>
<ul>
<li
v-for="todo in store.visibleTodos"
:key="todo.id"
:style="{ textDecoration: todo.completed ? 'line-through' : 'none' }"
@click="store.toggleTodo(todo.id)"
>
{
{ todo.text }}
</li>
</ul>
</div>
`
};
🔄 第三难:组件通信 - 数据的"乾坤大挪移"
问题:在React和Vue中,如何实现组件之间的数据传递和通信?有哪些最佳实践?
深度技术:
组件通信是前端开发中的核心问题。React和Vue提供了多种组件通信方式,从简单的props传递到复杂的状态管理,从事件总线到上下文共享。理解这些通信方式的适用场景和最佳实践,是构建可维护应用的关键。
代码示例:
// React组件通信示例
// 1. Props传递 - 父子组件通信
function ParentComponent() {
const [count, setCount] = useState(0);
return (
<div>
<h1>父组件</h1>
<ChildComponent
count={
count}
onIncrement={
() => setCount(c => c + 1)}
/>
</div>
);
}
function ChildComponent({
count, onIncrement }) {
return (
<div>
<p>子组件接收到的count: {
count}</p>
<button onClick={
onIncrement}>增加</button>
</div>
);
}
// 2. Context API - 跨层级组件通信
const ThemeContext = React.createContext('light');
function ThemeProvider({
children }) {
const [theme, setTheme] = useState('light');
const toggleTheme = () => {
setTheme(prev => prev === 'light' ? 'dark' : 'light');
};
return (
<ThemeContext.Provider value={
{
theme, toggleTheme }}>
{
children}
</ThemeContext.Provider>
);
}