What is the difference between synchronous and asynchronous programming (in node.js)

Question

I\'ve been reading nodebeginner And I came across the following two pieces of code.

The first one:

    var result = database.query(\"SELECT * FROM hu         


        

Answer 1

Asynchronous programming in JS:

Synchronous

• Stops execution of further code until this is done.
• Because it this stoppage of further execution, synchronous code is called 'blocking'. Blocking in the sense that no other code will be executed.

Asynchronous

• Execution of this is deferred to the event loop, this is a construct in a JS virtual machine which executes asynchronous functions (after the stack of synchronous functions is empty).
• Asynchronous code is called non blocking because it doesn't block further code from running.

Example:

// This function is synchronous
function log(arg) {
    console.log(arg)
}

log(1);

// This function is asynchronous
setTimeout(() => {
    console.log(2)
}, 0);

log(3)

• The example logs 1, 3, 2.
• 2 is logged last because it is inside a asynchronous function which is executed after the stack is empty.