ECMAScript-6 came with the default option to configure default parameters

Consider the following block of code:

const schedule = (status = "Busy") => "Current status: " + status;

// firstOutput
console.log(schedule("Available"));
// what will firstOutput log to the console?

// secondOutput
console.log(schedule());
// what will secondOutput log to the console?

Based on the above example, the firstOutput will log to the console:

"Current status: Available"

This is due to the specification of an argument ("Available" in this case) for our "status" parameter.

In the secondOutput, this result will be logged to the console:

"Current status: Busy"

Here in the secondOutput, the parameter name will receive a default value, ("Busy" in this case). This is as a result of not specifying an argument (or a value) for the parameter (We can say at this point that the parameter is undefined), hence resulting to the default.

// See here. A value or argument is NOT defined.
// Hence defaults to the default value
   console.log(greeting());

// But in this case, 
// A value or argument was defined ("Available" in this case)
   console.log(greeting(Available));`

The good thing about this "default parameters" feature in ES6, is that it encourages flexibility when writing functions.

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