Asynchronous JavaScript

Hey, time-traveling coder! ⏰ You’ve mastered DOM manipulation and ES6+ features—now it’s time to conquer asynchronous JavaScript, the magic that lets your code handle tasks that take time, like fetching data, waiting for timers, or responding to user clicks without freezing the page. JavaScript is single-threaded (one task at a time), but async tricks make it feel multitasking!

In this section, we’ll dive deeper into callbacks (building on the intro from advanced functions), explore Promises for better async flow, and use async/await for clean, readable code. By the end, you’ll be ready to handle delays like a pro. Let’s sync up with async! 🕹️

Callbacks: The Async Pioneers 📞 (Deep Dive)

You met callbacks in the advanced functions section—a function passed to another to run later. In async programming, callbacks are the OG way to handle tasks that take time, like timers or network requests.

How Callbacks Work

A callback is passed to an async function and called when the task finishes (or fails).

Example: Timeout party

function delayedGreeting(name, callback) {
    setTimeout(() => {
        callback(`Hello, ${name}! 🎉`);
    }, 2000); // Wait 2 seconds
}
delayedGreeting("Luna", message => console.log(message));
// Output after 2s: Hello, Luna! 🎉

Handling Errors

Callbacks often pass an error as the first argument (convention: “error-first callbacks”).

Example:

function fetchData(id, callback) {
    setTimeout(() => {
        if (id <= 0) {
            callback(new Error("Invalid ID!"));
        } else {
            callback(null, { id, name: "User" + id });
        }
    }, 1000);
}
fetchData(1, (err, data) => {
    if (err) {
        console.error(err.message);
    } else {
        console.log(data); // { id: 1, name: "User1" }
    }
});
fetchData(0, (err, data) => {
    console.error(err.message); // Invalid ID!
});

Callback Hell

Nesting callbacks leads to messy, pyramid-shaped code (aka “callback hell”).

Example:

setTimeout(() => {
    console.log("Step 1");
    setTimeout(() => {
        console.log("Step 2");
        setTimeout(() => {
            console.log("Step 3");
        }, 1000);
    }, 1000);
}, 1000);
// Output: Step 1 (1s), Step 2 (2s), Step 3 (3s)

When to Use

Callbacks are great for simple async tasks or older APIs. For complex flows, Promises or async/await are cleaner.

Avoid the Pyramid

Deeply nested callbacks are hard to read and debug. Use Promises to escape callback hell!

Promises: A Cleaner Async Path 🛤️

Promises are objects that represent a future value—either a result or an error. They’re like a ticket you get while waiting for your coffee order: it’ll either be fulfilled (coffee’s ready!) or rejected (out of beans).

Promise Basics

A Promise has three states:

Pending: Waiting for the result.
Fulfilled: Success with a value.
Rejected: Failed with an error.

Structure:

let promise = new Promise((resolve, reject) => {
    // Async task
    if (success) {
        resolve(value);
    } else {
        reject(error);
    }
});

Example: Fake data fetch

function getUser(id) {
    return new Promise((resolve, reject) => {
        setTimeout(() => {
            if (id > 0) {
                resolve({ id, name: "User" + id });
            } else {
                reject(new Error("Invalid ID"));
            }
        }, 1000);
    });
}
getUser(1)
    .then(data => console.log(data)) // { id: 1, name: "User1" }
    .catch(err => console.error(err.message));
getUser(0)
    .catch(err => console.error(err.message)); // Invalid ID

.then(): Handle success (gets the resolved value).
.catch(): Handle errors (gets the rejected error).
Chainable: .then(data => anotherPromise).then(...).

Fix callback hell:

getUser(1)
    .then(user => {
        console.log("Got user:", user);
        return getUser(2);
    })
    .then(user2 => console.log("Got user 2:", user2))
    .catch(err => console.error(err.message));

Promise Methods

Promise.all([promise1, promise2]): Waits for all to resolve or one to reject.

Promise.all([getUser(1), getUser(2)])
    .then(users => console.log(users)); // [{ id: 1, name: "User1" }, { id: 2, name: "User2" }]

Promise.race([promise1, promise2]): Resolves/rejects with the first to finish.

Why Promises?

Promises flatten async code, make error handling easier, and support chaining for sequential tasks.

Unhandled Rejections

Always use .catch()—unhandled Promise rejections can crash your app in some environments!

async/await: The Modern Async Hero 🦸

async/await (ES2017) builds on Promises, making async code look synchronous and super readable. It’s like writing a story instead of juggling callbacks or .then chains.

How It Works

async: Marks a function as returning a Promise.
await: Pauses until a Promise resolves (only inside async functions).

Example: Clean user fetch

async function fetchUser(id) {
    try {
        let user = await getUser(id); // Waits for Promise
        console.log(user);
        let user2 = await getUser(id + 1);
        console.log(user2);
    } catch (err) {
        console.error(err.message);
    }
}
fetchUser(1);
// Output: { id: 1, name: "User1" }, { id: 2, name: "User2" }

With DOM

<button id="fetchBtn">Fetch User</button>
<div id="output"></div>

async function displayUser() {
    let output = document.getElementById("output");
    output.textContent = "Loading...";
    try {
        let user = await getUser(1);
        output.textContent = `User: ${user.name}`;
    } catch (err) {
        output.textContent = `Error: ${err.message}`;
    }
}
document.getElementById("fetchBtn").addEventListener("click", displayUser);

try/catch: Handles errors like .catch.
await only works in async functions.

Combine with Promise.all for parallel tasks:

let [user1, user2] = await Promise.all([getUser(1), getUser(2)]);

Why async/await?

It reads like regular code, reduces nesting, and makes error handling intuitive with try/catch.

Await Scope

await must be inside an async function. Use IIFEs for top-level awaits in older environments: (async () => { await ... })();.

Practice Time! 🛠️

Try this mini-project to combine async concepts:

<!DOCTYPE html>
<html>
<head>
    <title>Async User Loader</title>
    <style>
        .card { padding: 20px; border: 1px solid #ccc; margin: 10px; }
        .error { color: red; }
    </style>
</head>
<body>
    <h1>Async User Loader 🌐</h1>
    <input id="userId" type="number" placeholder="Enter user ID">
    <button id="loadBtn">Load User</button>
    <div id="output" class="card"></div>
    <script>
        function getUser(id) {
            return new Promise((resolve, reject) => {
                setTimeout(() => {
                    if (id > 0 && id <= 3) {
                        resolve({ id, name: `User${id}` });
                    } else {
                        reject(new Error("Invalid user ID"));
                    }
                }, 1000);
            });
        }

        async function loadUser() {
            let output = document.getElementById("output");
            let id = Number(document.getElementById("userId").value);
            output.textContent = "Loading...";
            try {
                let user = await getUser(id);
                output.textContent = `User: ${user.name}`;
                output.classList.remove("error");
            } catch (err) {
                output.textContent = err.message;
                output.classList.add("error");
            }
        }

        document.getElementById("loadBtn").addEventListener("click", loadUser);
    </script>
</body>
</html>

Enter an ID (1–3), click Load—see the user or an error!
Uses Promises, async/await, DOM, and error handling.
Play: Add a “Load All Users” button with Promise.all.

What’s Next?

You’re an async master, handling delays with callbacks, Promises, and async/await! Next, we’ll explore JSON and APIs to fetch and work with real-world data. Zoom to JSON and APIs for the next adventure. You’re rocking this—keep it up! 💪

Questions? Check out our GitHub Discussions. Code on! ✨

Async/Await Deep Dive

Welcome to the async/await deep dive! 🌊 Now that you know the basics, let’s explore async/await in depth. We’ll cover advanced patterns, best practices, and performance tips to supercharge your async JavaScript skills. Ready? Let’s dive in!

Interactive Example: Async Task Manager

Build a task manager app to practice async/await with a real-world scenario.

Features

Add, update, delete tasks
Mark tasks as complete/incomplete
Display task stats (total, completed, pending)
Simulate server delays for realism

HTML

<!DOCTYPE html>
<html>
<head>
    <title>Async Task Manager</title>
    <style>
        body { font-family: Arial, sans-serif; margin: 0; padding: 0; }
        .container { max-width: 800px; margin: 50px auto; padding: 20px; border: 1px solid #ccc; border-radius: 8px; }
        h1 { text-align: center; }
        .task-form { margin-bottom: 20px; }
        .task-form input, .task-form button { padding: 10px; margin: 5px 0; width: 100%; }
        .task-list { margin-top: 20px; }
        .task { padding: 10px; border: 1px solid #ddd; border-radius: 4px; margin: 10px 0; }
        .task.completed { background-color: #e0ffe0; }
        .task-actions { margin-top: 10px; }
        .btn-complete, .btn-delete { padding: 10px 15px; margin-right: 10px; border: none; border-radius: 4px; cursor: pointer; }
        .btn-complete { background-color: #28a745; color: white; }
        .btn-delete { background-color: #dc3545; color: white; }
        .status { padding: 10px; margin: 10px 0; border-radius: 4px; }
        .status.success { background-color: #d4edda; color: #155724; }
        .status.error { background-color: #f8d7da; color: #721c24; }
        .stats { display: flex; gap: 20px; margin: 20px 0; }
        .stat { text-align: center; }
    </style>
</head>
<body>
    <div class="container">
        <h1>📋 Async Task Manager</h1>
        
        <div class="task-form">
            <h2>Add New Task</h2>
            <input id="taskTitle" type="text" placeholder="Task title" required>
            <textarea id="taskDescription" placeholder="Task description"></textarea>
            <button id="addTaskBtn">Add Task</button>
        </div>

        <div class="stats">
            <div class="stat">
                <h3 id="totalTasks">0</h3>
                <p>Total Tasks</p>
            </div>
            <div class="stat">
                <h3 id="completedTasks">0</h3>
                <p>Completed</p>
            </div>
            <div class="stat">
                <h3 id="pendingTasks">0</h3>
                <p>Pending</p>
            </div>
        </div>

        <div id="status" class="status" style="display: none;"></div>
        <div id="taskList" class="task-list"></div>
    </div>

    <script>
        class TaskManager {
            constructor() {
                this.tasks = [];
                this.nextId = 1;
                this.init();
            }
            
            async init() {
                await this.loadTasks();
                this.renderTasks();
                this.updateStats();
                this.setupEventListeners();
            }
            
            // Simulate async operations with delays
            async saveTask(task) {
                return new Promise((resolve) => {
                    setTimeout(() => {
                        this.tasks.push({ ...task, id: this.nextId++ });
                        resolve();
                    }, 500);
                });
            }
            
            async updateTask(id, updates) {
                return new Promise((resolve, reject) => {
                    setTimeout(() => {
                        const taskIndex = this.tasks.findIndex(t => t.id === id);
                        if (taskIndex === -1) {
                            reject(new Error('Task not found'));
                        } else {
                            this.tasks[taskIndex] = { ...this.tasks[taskIndex], ...updates };
                            resolve();
                        }
                    }, 300);
                });
            }
            
            async deleteTask(id) {
                return new Promise((resolve) => {
                    setTimeout(() => {
                        this.tasks = this.tasks.filter(t => t.id !== id);
                        resolve();
                    }, 400);
                });
            }
            
            async loadTasks() {
                // Simulate loading from server
                return new Promise((resolve) => {
                    setTimeout(() => {
                        // Pre-populate with some tasks
                        this.tasks = [
                            { id: 1, title: 'Learn Async/Await', description: 'Master asynchronous JavaScript', completed: false },
                            { id: 2, title: 'Build a Project', description: 'Apply async knowledge', completed: true },
                            { id: 3, title: 'Practice Error Handling', description: 'Use try/catch effectively', completed: false }
                        ];
                        this.nextId = 4;
                        resolve();
                    }, 800);
                });
            }
            
            showStatus(message, type = 'loading') {
                const status = document.getElementById('status');
                status.textContent = message;
                status.className = `status ${type}`;
                status.style.display = 'block';
                
                if (type !== 'loading') {
                    setTimeout(() => {
                        status.style.display = 'none';
                    }, 3000);
                }
            }
            
            hideStatus() {
                document.getElementById('status').style.display = 'none';
            }
            
            async addTask(title, description) {
                try {
                    this.showStatus('Adding task...', 'loading');
                    
                    const newTask = {
                        title: title.trim(),
                        description: description.trim(),
                        completed: false,
                        createdAt: new Date().toISOString()
                    };
                    
                    await this.saveTask(newTask);
                    
                    this.showStatus('Task added successfully!', 'success');
                    this.renderTasks();
                    this.updateStats();
                    
                    // Clear form
                    document.getElementById('taskTitle').value = '';
                    document.getElementById('taskDescription').value = '';
                    
                } catch (error) {
                    this.showStatus(`Failed to add task: ${error.message}`, 'error');
                }
            }
            
            async toggleTaskCompletion(id) {
                try {
                    const task = this.tasks.find(t => t.id === id);
                    if (!task) return;
                    
                    this.showTaskLoading(id, true);
                    
                    await this.updateTask(id, { 
                        completed: !task.completed,
                        completedAt: !task.completed ? new Date().toISOString() : null
                    });
                    
                    this.showStatus(
                        `Task ${task.completed ? 'marked as pending' : 'completed'}!`, 
                        'success'
                    );
                    
                    this.renderTasks();
                    this.updateStats();
                    
                } catch (error) {
                    this.showStatus(`Failed to update task: ${error.message}`, 'error');
                } finally {
                    this.showTaskLoading(id, false);
                }
            }
            
            async removeTask(id) {
                try {
                    const task = this.tasks.find(t => t.id === id);
                    if (!task) return;
                    
                    if (!confirm(`Delete "${task.title}"?`)) return;
                    
                    this.showTaskLoading(id, true);
                    
                    await this.deleteTask(id);
                    
                    this.showStatus('Task deleted!', 'success');
                    this.renderTasks();
                    this.updateStats();
                    
                } catch (error) {
                    this.showStatus(`Failed to delete task: ${error.message}`, 'error');
                }
            }
            
            showTaskLoading(id, loading) {
                const taskElement = document.querySelector(`[data-task-id="${id}"]`);
                if (taskElement) {
                    taskElement.classList.toggle('loading', loading);
                }
            }
            
            renderTasks() {
                const taskList = document.getElementById('taskList');
                
                if (this.tasks.length === 0) {
                    taskList.innerHTML = `
                        <div class="task">
                            <h3>No tasks yet! 🎯</h3>
                            <p>Add your first task above to get started.</p>
                        </div>
                    `;
                    return;
                }
                
                taskList.innerHTML = this.tasks
                    .sort((a, b) => new Date(b.createdAt) - new Date(a.createdAt))
                    .map(task => `
                        <div class="task ${task.completed ? 'completed' : ''}" data-task-id="${task.id}">
                            <h3>${task.title}</h3>
                            <p>${task.description}</p>
                            <p><small>Created: ${new Date(task.createdAt).toLocaleString()}</small></p>
                            ${task.completedAt ? `<p><small>Completed: ${new Date(task.completedAt).toLocaleString()}</small></p>` : ''}
                            <div class="task-actions">
                                <button class="btn-complete" onclick="taskManager.toggleTaskCompletion(${task.id})">
                                    ${task.completed ? '↶ Mark Pending' : '✓ Complete'}
                                </button>
                                <button class="btn-delete" onclick="taskManager.removeTask(${task.id})">
                                    🗑️ Delete
                                </button>
                            </div>
                        </div>
                    `).join('');
            }
            
            updateStats() {
                const total = this.tasks.length;
                const completed = this.tasks.filter(t => t.completed).length;
                const pending = total - completed;
                
                document.getElementById('totalTasks').textContent = total;
                document.getElementById('completedTasks').textContent = completed;
                document.getElementById('pendingTasks').textContent = pending;
            }
            
            setupEventListeners() {
                const addBtn = document.getElementById('addTaskBtn');
                const titleInput = document.getElementById('taskTitle');
                const descInput = document.getElementById('taskDescription');
                
                addBtn.addEventListener('click', () => {
                    const title = titleInput.value.trim();
                    const description = descInput.value.trim();
                    
                    if (!title) {
                        this.showStatus('Please enter a task title!', 'error');
                        return;
                    }
                    
                    this.addTask(title, description);
                });
                
                // Add task on Enter key
                titleInput.addEventListener('keypress', (e) => {
                    if (e.key === 'Enter') {
                        addBtn.click();
                    }
                });
            }
        }

        // Initialize task manager
        let taskManager;
        
        async function initApp() {
            try {
                document.getElementById('status').style.display = 'block';
                document.getElementById('status').textContent = 'Loading task manager...';
                document.getElementById('status').className = 'status loading';
                
                taskManager = new TaskManager();
                
            } catch (error) {
                document.getElementById('status').textContent = `Failed to load: ${error.message}`;
                document.getElementById('status').className = 'status error';
            }
        }

        // Start the app
        initApp();
    </script>
</body>
</html>

This comprehensive example demonstrates:

Class-based async architecture with proper error handling
Sequential and parallel operations (saving, updating, deleting)
Loading states and user feedback
Try/catch blocks for robust error handling
Real-world patterns like form validation and confirmation dialogs

Common Async/Await Patterns 🎨

1. Data Transformation Pipeline

async function processUserData(userId) {
    try {
        // Step 1: Fetch user
        const user = await fetchUser(userId);
        
        // Step 2: Enrich with profile data (parallel)
        const [profile, preferences, activity] = await Promise.all([
            fetchUserProfile(user.id),
            fetchUserPreferences(user.id),
            fetchUserActivity(user.id)
        ]);
        
        // Step 3: Transform and combine
        const enrichedUser = {
            ...user,
            profile: {
                ...profile,
                lastSeen: new Date(activity.lastLogin).toLocaleDateString()
            },
            settings: preferences,
            activityScore: calculateActivityScore(activity)
        };
        
        // Step 4: Save processed data
        await saveProcessedUser(enrichedUser);
        
        return enrichedUser;
        
    } catch (error) {
        console.error('User processing failed:', error);
        throw new Error(`Failed to process user ${userId}: ${error.message}`);
    }
}

2. Concurrent Processing with Limits

async function processBatch(items, concurrency = 3) {
    const results = [];
    
    for (let i = 0; i < items.length; i += concurrency) {
        const batch = items.slice(i, i + concurrency);
        
        console.log(`Processing batch ${Math.floor(i / concurrency) + 1}/${Math.ceil(items.length / concurrency)}`);
        
        const batchPromises = batch.map(async (item) => {
            try {
                return await processItem(item);
            } catch (error) {
                console.error(`Failed to process item ${item.id}:`, error);
                return { error: error.message, item };
            }
        });
        
        const batchResults = await Promise.all(batchPromises);
        results.push(...batchResults);
        
        // Optional: small delay between batches
        if (i + concurrency < items.length) {
            await delay(100);
        }
    }
    
    return results;
}

3. Graceful Degradation

async function loadDashboard(userId) {
    const dashboard = {
        user: null,
        posts: [],
        notifications: [],
        weather: null
    };
    
    try {
        // Critical data - must succeed
        dashboard.user = await fetchUser(userId);
    } catch (error) {
        throw new Error(`Cannot load dashboard: ${error.message}`);
    }
    
    // Non-critical data - continue on failure
    try {
        dashboard.posts = await fetchUserPosts(userId);
    } catch (error) {
        console.warn('Failed to load posts:', error.message);
        dashboard.posts = [];
    }
    
    try {
        dashboard.notifications = await fetchNotifications(userId);
    } catch (error) {
        console.warn('Failed to load notifications:', error.message);
        dashboard.notifications = [];
    }
    
    try {
        dashboard.weather = await fetchWeatherData(dashboard.user.location);
    } catch (error) {
        console.warn('Failed to load weather:', error.message);
        dashboard.weather = { error: 'Weather unavailable' };
    }
    
    return dashboard;
}

Best Practices Checklist ✅

✅ Do's

Always use try/catch for error handling

async function safeOperation() {
    try {
        const result = await riskyOperation();
        return result;
    } catch (error) {
        console.error('Operation failed:', error);
        throw error; // or handle gracefully
    }
}

Use Promise.all for parallel operations

// Good - parallel execution
const [user, posts, comments] = await Promise.all([
    fetchUser(id),
    fetchPosts(id),
    fetchComments(id)
]);

// Bad - sequential execution
const user = await fetchUser(id);
const posts = await fetchPosts(id);
const comments = await fetchComments(id);

Handle loading states in UI applications

async function updateUI() {
    setLoading(true);
    try {
        const data = await fetchData();
        updateDisplay(data);
    } catch (error) {
        showError(error.message);
    } finally {
        setLoading(false);
    }
}

❌ Don'ts

Don't forget await

// Bad - returns Promise, not value
async function bad() {
    const result = fetchData(); // Missing await!
    return result.name; // Error: result is a Promise
}

// Good
async function good() {
    const result = await fetchData();
    return result.name;
}

Don't use async/await in loops incorrectly

// Bad - sequential processing
for (const item of items) {
    await processItem(item); // Waits for each one
}

// Good - parallel processing
const promises = items.map(item => processItem(item));
const results = await Promise.all(promises);

Don't ignore error handling

// Bad - unhandled errors
async function bad() {
    const result = await riskyOperation(); // Could throw
    return result;
}

// Good
async function good() {
    try {
        const result = await riskyOperation();
        return result;
    } catch (error) {
        console.error('Error:', error);
        return null; // or appropriate fallback
    }
}

Performance Tips 🚀

1. Minimize Sequential Dependencies

// Slow - unnecessary sequential execution
async function slow(userId) {
    const user = await fetchUser(userId);
    const posts = await fetchPosts(userId); // Doesn't depend on user
    const profile = await fetchProfile(user.id); // Depends on user
    return { user, posts, profile };
}

// Fast - minimize sequential dependencies
async function fast(userId) {
    const userPromise = fetchUser(userId);
    const postsPromise = fetchPosts(userId); // Start immediately
    
    const user = await userPromise;
    const [posts, profile] = await Promise.all([
        postsPromise,
        fetchProfile(user.id) // Start after user is available
    ]);
    
    return { user, posts, profile };
}

2. Use AbortController for Cancellation

async function fetchWithCancel(url, timeoutMs = 5000) {
    const controller = new AbortController();
    const timeoutId = setTimeout(() => controller.abort(), timeoutMs);
    
    try {
        const response = await fetch(url, {
            signal: controller.signal
        });
        clearTimeout(timeoutId);
        return await response.json();
    } catch (error) {
        if (error.name === 'AbortError') {
            throw new Error('Request timed out');
        }
        throw error;
    }
}

Debugging Async Code 🐛

Common Issues and Solutions

Unhandled Promise Rejections

// Add global handlers
window.addEventListener('unhandledrejection', event => {
    console.error('Unhandled promise rejection:', event.reason);
    event.preventDefault(); // Prevent default browser behavior
});

Debugging Async Flow

async function debuggableFunction() {
    console.log('Starting operation...');
    
    try {
        console.log('Fetching user...');
        const user = await fetchUser(1);
        console.log('User fetched:', user);
        
        console.log('Processing user...');
        const processed = await processUser(user);
        console.log('User processed:', processed);
        
        return processed;
    } catch (error) {
        console.error('Error at step:', error);
        throw error;
    }
}

Testing Async Functions

// Testing with async/await
async function testAsyncFunction() {
    try {
        const result = await myAsyncFunction();
        console.assert(result.id === 1, 'ID should be 1');
        console.log('Test passed! ✅');
    } catch (error) {
        console.error('Test failed:', error);
    }
}

What's Next? 🎯

Congratulations! You've mastered async/await, the most modern and readable way to handle asynchronous JavaScript. You now understand:

How to write clean, readable async code
Proper error handling with try/catch
Performance optimization with parallel execution
Real-world patterns and best practices

Your async journey is complete! With callbacks, Promises, and async/await in your toolkit, you're ready to handle any asynchronous challenge JavaScript throws at you.

Next up: Ready to put your async skills to use? Check out our JSON and APIs section to learn how to fetch and work with real data from servers!

Final Async Wisdom

Async/await is powerful but remember: with great power comes great responsibility. Always handle errors, optimize for performance, and keep your code readable. Your future self will thank you! 🙏

You Did It! 🎉

You've conquered one of JavaScript's most challenging topics! Async programming is a superpower that separates good developers from great ones. Keep practicing and soon async code will feel as natural as breathing! 💪

Callbacks: The Async Pioneers 📞 (Deep Dive)​

How Callbacks Work​

Handling Errors​

Callback Hell​

Promises: A Cleaner Async Path 🛤️​

Promise Basics​

Promise Methods​

async/await: The Modern Async Hero 🦸​

How It Works​

With DOM​

Practice Time! 🛠️​

What’s Next?​

Async/Await Deep Dive

Interactive Example: Async Task Manager​

Features​

HTML​

Common Async/Await Patterns 🎨​

1. Data Transformation Pipeline​

2. Concurrent Processing with Limits​

3. Graceful Degradation​

Best Practices Checklist ✅​

✅ Do's​

❌ Don'ts​

Performance Tips 🚀​

1. Minimize Sequential Dependencies​

2. Use AbortController for Cancellation​

Debugging Async Code 🐛​

Common Issues and Solutions​

What's Next? 🎯​