Synchronous

JavaScript is a single threaded language and has a synchronous execution model. Single threaded means javascript code executed line by line. Every line of code waits for its previous one to get executed first and then it gets executed.

const processOrder = (customer) => {
    console.log('Processing order for customer 1');

    let currentTime = new Date().getTime();
    while (currentTime + 10000 >= new Date().getTime());
    console.log('Order processed for customer 1');
}

console.log('Take order for customer 1');
processOrder();
console.log('Completed order for customer 1');