Module 14 Notes

Study Notes: Control Structures and Functions in JavaScript

1. What is Asynchronous JavaScript?

Javascript is single-threaded. To prevent page freezes during network requests or timers, Javascript runs them asynchronously in the browser background, returning a Promise when finished.

2. Promises vs Async/Await Patterns

Using async and await allows asynchronous code to be read line-by-line sequentially like synchronous code, avoiding complex nested callbacks.

3. Fetching API Endpoints Template

// Fetching mock users data asynchronously using async/await
async function loadUsers() {
    try {
        const response = await fetch('https://jsonplaceholder.typicode.com/users');
        if (!response.ok) {
            throw new Error('Network error: ' + response.status);
        }
        const users = await response.json();
        console.log("Fetched Users Count:", users.length);
        console.log("First User Name:", users[0].name);
    } catch (error) {
        console.error("API Fetch Failed:", error.message);
    }
}

// Execute call
loadUsers();

Expected University & Placement Questions

• Q1: Outline how this module applies to modern production web design workflows.
  Answer: This topic forms a crucial layer of web architecture (structure, utility styling, logic control, package loading, or data persistence), enabling reliable, scalable web application engineering.
• Q2: How do you verify and debug syntax errors in this framework?
  Answer: Use browser developer consoles to review JavaScript alerts, run terminal linter commands on backend scripts, and verify data transfers in network panels.