- Create a JavaScript function that loops through a function
Array
Since functions in JavaScript are "first-class" objects, it means they can be
treated like any other data type in JavaScript (Number
, String
, et al.). A
fun way to experience this truth is to load up an Array
of Functions
and
then call each Function
.
Let's create an Array
of dog-care functions so that we can report on the
activities we take in caring for Byron the Poodle.
When this program runs, it should print out:
console.log("Wake Byron the poodle");
console.log("Leash Byron the poodle");
console.log("Walk to the park with Byron the poodle");
console.log("Throw the frisbee for Byron the poodle");
console.log("Walk home with Byron the poodle");
console.log("Unleash Byron the poodle");
Start by creating a function for every activity that you see listed above:
For example:
function wakeDog() {
console.log("Wake Byron the poodle");
}
...
But wait, if we write it in this way, all of our uses of this function will be
for Byron the poodle
. Let's generalize now and make each function take a
dogName
and dogBreed
parameter. Thus:
function wakeDog(dogName, dogBreed) {
console.log(`Wake ${dogName} the ${dogBreed}`);
}
...
Additionally: Each function should return the string that it creates. That
is, we should create a String
, console.log()
it, and return that String
.
Continue writing "generalized" functions for
wakeDog
leashDog
walkToPark
throwFrisbee
walkHome
unleashDog
Each function's implementation will be a generalized invocation of
console.log()
.
Next, create our "Array o' Functions!" Create a variable called routine
. This
variable will be an Array
all of the functions we've just defined.
Lastly, create the function called exerciseDog
that will take in two
arguments:
dogName
dogBreed
The function's implementation should
- Iterate over the
routine
Array
- Call each function in the array and
- pass the
dogName
anddogBreed
received byexerciseDog()
to the function as they are called - capture the result of each function's call
- return an
Array
of all those functions' return values
This lab demonstrates the power of Function
s as first-class data. We can
stack them up in Arrays
or assign them inside of Objects
or save them to
variables, or iterate over them. Instead of merely having Array
s of
String
s and other familiar items, we can stuff them with work. And that's
nothing short of amazing!