sanbuphy
d35211071a
- standardize border-radius from 8px to 6px for consistent styling - adjust padding values from 1rem to 0.75rem for better visual hierarchy - remove redundant overflow-y properties for cleaner code
364 lines
8.3 KiB
Vue
364 lines
8.3 KiB
Vue
<template>
|
||
<div class="macro-micro-task-demo">
|
||
<div class="demo-header">
|
||
<span class="icon">🔄</span>
|
||
<span class="title">宏任务与微任务</span>
|
||
<span class="subtitle">事件循环中的任务优先级</span>
|
||
</div>
|
||
|
||
<div class="intro-text">
|
||
JavaScript 是单线程的，但可以通过<span class="highlight">任务队列</span>实现异步。就像餐厅只有一个厨师，但他可以同时处理多个订单：先做VIP订单（微任务），再做普通订单（宏任务）。
|
||
</div>
|
||
|
||
<div class="demo-content">
|
||
<div class="event-loop-flow">
|
||
<div class="flow-container">
|
||
<div class="flow-section main-thread">
|
||
<div class="section-title">主线程（执行栈）</div>
|
||
<div class="execution-box">
|
||
<div class="exec-item" :class="{ active: currentStep === 'script' }">
|
||
<span class="exec-label">同步代码</span>
|
||
</div>
|
||
</div>
|
||
</div>
|
||
|
||
<div class="flow-section task-queues">
|
||
<div class="section-title">任务队列</div>
|
||
<div class="queues-container">
|
||
<div class="queue-box micro">
|
||
<div class="queue-title">微任务队列（优先级高）</div>
|
||
<div class="queue-items">
|
||
<div
|
||
v-for="task in microTasks"
|
||
:key="task.id"
|
||
class="queue-item"
|
||
:class="{ active: task.isActive, processing: task.isProcessing }"
|
||
>
|
||
{{ task.name }}
|
||
</div>
|
||
</div>
|
||
</div>
|
||
|
||
<div class="queue-box macro">
|
||
<div class="queue-title">宏任务队列（优先级低）</div>
|
||
<div class="queue-items">
|
||
<div
|
||
v-for="task in macroTasks"
|
||
:key="task.id"
|
||
class="queue-item"
|
||
:class="{ active: task.isActive, processing: task.isProcessing }"
|
||
>
|
||
{{ task.name }}
|
||
</div>
|
||
</div>
|
||
</div>
|
||
</div>
|
||
</div>
|
||
</div>
|
||
</div>
|
||
|
||
<div class="code-example">
|
||
<div class="example-title">代码示例</div>
|
||
<pre class="code-block"><code>console.log('1')
|
||
|
||
setTimeout(() => console.log('2'), 0) // 宏任务
|
||
|
||
Promise.resolve().then(() => console.log('3')) // 微任务
|
||
|
||
console.log('4')
|
||
|
||
<span class="code-comment">// 输出顺序：1 → 4 → 3 → 2</span></code></pre>
|
||
</div>
|
||
|
||
<div class="control-panel">
|
||
<button class="run-btn" @click="runDemo">
|
||
{{ isRunning ? '🔄 运行中...' : '▶️ 运行演示' }}
|
||
</button>
|
||
</div>
|
||
</div>
|
||
|
||
<div class="info-box">
|
||
<span class="icon">💡</span>
|
||
<strong>核心要点：</strong>每次宏任务执行完后，会清空所有微任务，然后再执行下一个宏任务。这就是为什么 Promise.then() 比 setTimeout() 先执行。
|
||
</div>
|
||
</div>
|
||
</template>
|
||
|
||
<script setup>
|
||
import { ref } from 'vue'
|
||
|
||
const isRunning = ref(false)
|
||
const currentStep = ref('script')
|
||
|
||
const microTasks = ref([
|
||
{ id: 1, name: 'Promise.then()', isActive: false, isProcessing: false },
|
||
{ id: 2, name: 'queueMicrotask()', isActive: false, isProcessing: false }
|
||
])
|
||
|
||
const macroTasks = ref([
|
||
{ id: 1, name: 'setTimeout()', isActive: false, isProcessing: false },
|
||
{ id: 2, name: 'setInterval()', isActive: false, isProcessing: false },
|
||
{ id: 3, name: 'I/O 操作', isActive: false, isProcessing: false }
|
||
])
|
||
|
||
async function runDemo() {
|
||
if (isRunning.value) return
|
||
isRunning.value = true
|
||
|
||
// Reset
|
||
microTasks.value.forEach(t => {
|
||
t.isActive = false
|
||
t.isProcessing = false
|
||
})
|
||
macroTasks.value.forEach(t => {
|
||
t.isActive = false
|
||
t.isProcessing = false
|
||
})
|
||
|
||
// Step 1: Sync code
|
||
currentStep.value = 'script'
|
||
await sleep(800)
|
||
|
||
// Step 2: Process microtasks
|
||
microTasks.value[0].isActive = true
|
||
await sleep(500)
|
||
microTasks.value[0].isActive = false
|
||
microTasks.value[0].isProcessing = true
|
||
await sleep(600)
|
||
microTasks.value[0].isProcessing = false
|
||
|
||
microTasks.value[1].isActive = true
|
||
await sleep(500)
|
||
microTasks.value[1].isActive = false
|
||
microTasks.value[1].isProcessing = true
|
||
await sleep(600)
|
||
microTasks.value[1].isProcessing = false
|
||
|
||
// Step 3: Process one macrotask
|
||
macroTasks.value[0].isActive = true
|
||
await sleep(500)
|
||
macroTasks.value[0].isActive = false
|
||
macroTasks.value[0].isProcessing = true
|
||
await sleep(600)
|
||
macroTasks.value[0].isProcessing = false
|
||
|
||
currentStep.value = ''
|
||
isRunning.value = false
|
||
}
|
||
|
||
function sleep(ms) {
|
||
return new Promise(resolve => setTimeout(resolve, ms))
|
||
}
|
||
</script>
|
||
|
||
<style scoped>
|
||
.macro-micro-task-demo {
|
||
border: 1px solid var(--vp-c-divider);
|
||
border-radius: 6px;
|
||
background: var(--vp-c-bg-soft);
|
||
padding: 0.75rem;
|
||
margin: 0.5rem 0;
|
||
}
|
||
|
||
.demo-header {
|
||
display: flex;
|
||
align-items: center;
|
||
gap: 0.5rem;
|
||
margin-bottom: 0.75rem;
|
||
}
|
||
|
||
.demo-header .icon { font-size: 1.25rem; }
|
||
.demo-header .title { font-weight: bold; font-size: 1rem; }
|
||
.demo-header .subtitle { color: var(--vp-c-text-2); font-size: 0.85rem; margin-left: 0.5rem; }
|
||
|
||
.intro-text {
|
||
font-size: 0.9rem;
|
||
color: var(--vp-c-text-2);
|
||
line-height: 1.6;
|
||
margin-bottom: 1rem;
|
||
padding: 0.75rem;
|
||
background: var(--vp-c-bg);
|
||
border-radius: 6px;
|
||
}
|
||
|
||
.intro-text .highlight {
|
||
color: var(--vp-c-brand-1);
|
||
font-weight: 500;
|
||
}
|
||
|
||
.demo-content {
|
||
background: var(--vp-c-bg);
|
||
border-radius: 6px;
|
||
padding: 0.75rem;
|
||
}
|
||
|
||
.event-loop-flow {
|
||
margin-bottom: 1rem;
|
||
}
|
||
|
||
.flow-container {
|
||
display: flex;
|
||
gap: 1rem;
|
||
}
|
||
|
||
.flow-section {
|
||
flex: 1;
|
||
}
|
||
|
||
.section-title {
|
||
font-size: 0.8rem;
|
||
font-weight: 500;
|
||
color: var(--vp-c-text-2);
|
||
margin-bottom: 0.5rem;
|
||
text-align: center;
|
||
}
|
||
|
||
.execution-box {
|
||
background: var(--vp-c-bg-soft);
|
||
border-radius: 6px;
|
||
padding: 0.75rem;
|
||
min-height: 80px;
|
||
display: flex;
|
||
align-items: center;
|
||
justify-content: center;
|
||
}
|
||
|
||
.exec-item {
|
||
padding: 0.5rem 1rem;
|
||
background: var(--vp-c-bg-alt);
|
||
border-radius: 4px;
|
||
font-size: 0.85rem;
|
||
color: var(--vp-c-text-2);
|
||
transition: all 0.3s ease;
|
||
}
|
||
|
||
.exec-item.active {
|
||
background: var(--vp-c-brand);
|
||
color: white;
|
||
transform: scale(1.05);
|
||
}
|
||
|
||
.queues-container {
|
||
display: flex;
|
||
flex-direction: column;
|
||
gap: 0.75rem;
|
||
}
|
||
|
||
.queue-box {
|
||
background: var(--vp-c-bg-soft);
|
||
border-radius: 6px;
|
||
padding: 0.75rem;
|
||
}
|
||
|
||
.queue-title {
|
||
font-size: 0.75rem;
|
||
color: var(--vp-c-text-2);
|
||
margin-bottom: 0.5rem;
|
||
font-weight: 500;
|
||
}
|
||
|
||
.queue-box.micro .queue-title {
|
||
color: var(--vp-c-brand-1);
|
||
}
|
||
|
||
.queue-box.macro .queue-title {
|
||
color: var(--vp-c-text-3);
|
||
}
|
||
|
||
.queue-items {
|
||
display: flex;
|
||
flex-direction: column;
|
||
gap: 0.4rem;
|
||
}
|
||
|
||
.queue-item {
|
||
padding: 0.4rem 0.6rem;
|
||
background: var(--vp-c-bg);
|
||
border: 1px solid var(--vp-c-divider);
|
||
border-radius: 4px;
|
||
font-size: 0.75rem;
|
||
font-family: 'Courier New', monospace;
|
||
color: var(--vp-c-text-2);
|
||
transition: all 0.3s ease;
|
||
}
|
||
|
||
.queue-item.active {
|
||
border-color: var(--vp-c-brand);
|
||
background: var(--vp-c-brand-soft);
|
||
color: var(--vp-c-brand-1);
|
||
font-weight: 500;
|
||
}
|
||
|
||
.queue-item.processing {
|
||
background: var(--vp-c-success);
|
||
color: white;
|
||
border-color: var(--vp-c-success);
|
||
}
|
||
|
||
.code-example {
|
||
margin-bottom: 1rem;
|
||
}
|
||
|
||
.example-title {
|
||
font-size: 0.8rem;
|
||
font-weight: 500;
|
||
color: var(--vp-c-text-2);
|
||
margin-bottom: 0.5rem;
|
||
}
|
||
|
||
.code-block {
|
||
background: var(--vp-c-bg-soft);
|
||
border-radius: 6px;
|
||
padding: 0.75rem;
|
||
margin: 0;
|
||
overflow-x: auto;
|
||
}
|
||
|
||
.code-block code {
|
||
font-family: 'Courier New', monospace;
|
||
font-size: 0.75rem;
|
||
line-height: 1.6;
|
||
color: var(--vp-c-text-1);
|
||
}
|
||
|
||
.code-comment {
|
||
color: var(--vp-c-text-3);
|
||
}
|
||
|
||
.control-panel {
|
||
display: flex;
|
||
justify-content: center;
|
||
}
|
||
|
||
.run-btn {
|
||
padding: 0.5rem 1.5rem;
|
||
background: var(--vp-c-brand);
|
||
color: white;
|
||
border: none;
|
||
border-radius: 6px;
|
||
font-size: 0.9rem;
|
||
cursor: pointer;
|
||
transition: background 0.2s;
|
||
}
|
||
|
||
.run-btn:hover {
|
||
background: var(--vp-c-brand-dark);
|
||
}
|
||
|
||
.run-btn:disabled {
|
||
opacity: 0.6;
|
||
cursor: not-allowed;
|
||
}
|
||
|
||
.info-box {
|
||
background: var(--vp-c-bg-alt);
|
||
padding: 0.75rem;
|
||
border-radius: 6px;
|
||
font-size: 0.85rem;
|
||
color: var(--vp-c-text-2);
|
||
margin-top: 0.75rem;
|
||
}
|
||
|
||
.info-box .icon { margin-right: 0.25rem; }
|
||
</style>
|