This section contains information about the JavaScript programming language. JavaScript is a dynamic programming language that was initially created for client-side web development. It has since then evolved into a client-side and server-side programming language. Its appeal has propelled it into a major programming language that has been used by countless developers. This in and of itself makes it hard for developers not to get acquainted with this programming language. I, for one, have been drawn to it by the fact that I have created some personal web pages that required using JavaScript to dynamically update those web pages. Even though it contains the word Java within its name. It has different features that are not part of the Java programming language. For instance, JavaScript is a single threaded event driven environment. Tasks that require feedback like I/O actions end up being placed on a waiting queue that allows the JavaScript engine the opportunity to execute another action that is ready to be processed. These events are managed by the JavaScript engine and insure that they are processed as they are available in a serialized fashion. This make it as such that one doesn’t need to worry about synchronizing data access since this is never an issue. This is probably one of the biggest advantage of JavaScript over something like Java. This ability to not need to worry about synchronizing data access greatly simplifies the development of JavaScript projects. I will describe the main feature of JavaScript that allows one to take advantage of the single threaded model that JavaScript uses.

Let us then start by taking a look at a simple JavaScript code.

function message(msg) {
    console.log(msg)
}

The above simple function just prints to the console the passed message msg. The function is defined as a regular function that will be executed without requiring any waiting. When the JavaScript engine runs this function. It will be executed without being place on a waiting queue. You can think of this function as a synchronized method. You can also define a function that will be put on a waiting queue as follows:

async function message(msg) {
    console.log(msg)
}

The difference between the prior implementation and this one is the addition of the async to the function definition. This means that upon calling this message the call will be placed on an event queue that will then wait until the method has completed prior to it continuing its execution. The caller will then only be able to know when this method has completed by using the await syntax or by using the returned object then method. For example:

await message('Hello, world!')
console.log('message has been displayed')

message('Hello, world!').then(() => {
    console.log('message has been displayed')
})

The two above calls produce similar results. I will talk more about the use of the above syntax since this is something that I have found interesting when using the JavaScript programming language.

To be continued….