What is the difference between synchronous and asynchronous code?

Synchronous code executes tasks sequentially, waiting for each to complete before moving to the next.

Asynchronous code allows tasks to run in the background without blocking the main execution thread and reacts to their completion when it occurs.

Main differences:

Characteristic	Synchronous code	Asynchronous code
Blocking	Blocks the execution thread	Does not block the execution thread
Execution	Sequential	Parallel (in the context of non-blocking UI)
Waiting	Waits for the operation to finish	Does not wait, continues execution
Application	Simple operations that do not require waiting	Network requests, file operations, timers

Example of synchronous (blocking) code:

// Request will block execution until response is received
const response = doSynchronousRequest('https://api.example.com/data');
console.log(response);
console.log('This line executes after receiving the response.');

Example of asynchronous (non-blocking) code:

// Request runs in the background
doAsynchronousRequest('https://api.example.com/data', (response) => {
  console.log(response); // This code runs upon receiving the response
});
console.log('This line runs immediately, without waiting for the response.');