var timeCreated = new Date();
button.onclick = function buttonClicked(clickEvent) {
var timeClicked = new Date();
console.log("Button was created " + (timeClicked-timeCreated) + "ms ago");
}
Lets say you have two functions: Jon from support, and Jane from billing. Both of them have access to the customer database.
Now a customer calls, the customer hits 1 for support and Jon gets the call, while Jon is on the phone, another customer calls, hits 2 for billing and Jane gets the call.
You can have a very complex setup using just functions, and some variables to keep track of things, maybe an array for implementing a call queue. You can choose when to run in serial, and when to run in parallel, and make a limit on how many calls that can run at any given time. And every possible error handled and managed. Promises, async/await and futures are only leaky abstractions that will just complicate things. They look nice for simple examples without any error handling, but when you want to do real world stuff you have to think about how they work behind the scenes.
You can have a very complex setup using just functions, and some variables to keep track of things, maybe an array for implementing a call queue. You can choose when to run in serial, and when to run in parallel, and make a limit on how many calls that can run at any given time. And every possible error handled and managed. Promises, async/await and futures are only leaky abstractions that will just complicate things. They look nice for simple examples without any error handling, but when you want to do real world stuff you have to think about how they work behind the scenes.