FAQ: Functions - Concise Body Arrow Functions

[wiki-bot]

This community-built FAQ covers the "Concise Body Arrow Functions " exercise from the lesson “Functions”.

Paths and Courses
This exercise can be found in the following Codecademy content:

Web Development

Introduction To JavaScript

FAQs on the exercise _Concise Body Arrow Functions _

There are currently no frequently asked questions associated with this exercise – that’s where you come in! You can contribute to this section by offering your own questions, answers, or clarifications on this exercise. Ask or answer a question by clicking reply () below.

If you’ve had an “aha” moment about the concepts, formatting, syntax, or anything else with this exercise, consider sharing those insights! Teaching others and answering their questions is one of the best ways to learn and stay sharp.

Join the Discussion. Help a fellow learner on their journey.

Ask or answer a question about this exercise by clicking reply () below!

Agree with a comment or answer? Like () to up-vote the contribution!

Need broader help or resources? Head here.

Looking for motivation to keep learning? Join our wider discussions.

Learn more about how to use this guide.

Found a bug? Report it!

Have a question about your account or billing? Reach out to our customer support team!

None of the above? Find out where to ask other questions here!

[matrenitski]

Even more concise code:

const plantNeedsWater = day => day === ‘Wednesday’;

console.log(plantNeedsWater(‘Wednesday’));

[mtf]

And we can write it this consisely, why?

[lindseykonich]

The solution to this exercise confused me a tad…

How are we able to use the concise body function when the correct answer is too long and still results in a multi-line block?

[mtf]

When there are multiple lines of code in the block, write it like a regular function expression (with curly braces and a return).

const foo = (baz, bar) => {
    // code
    // code
    // code
    return "some value"
};

[alexhansford]

I struggled with this exercise too.
Whilst concise functions sound useful - I prefer the more readable form of multi-line functions personally.
Still it’s useful to know!

[sirronmr]

I was good until the last page (review functions):

When I played around with the code I noticed:

const plantNeedsWater = day => day === 'Wednesday' ? 'Water me' : "Don't water me";

can also be on two lines

const plantNeedsWater = day => day === 'Wednesday' 
? 'Water me' : "Don't water me";

… without having to use the ‘return’ statement, or additional code. I was considering this if the true/false answers were a longer statement; to allow for better readability. Is this doable, or should I be considering a better way to keep the code ‘clean’?

[digitalmaster95902]

I am trying to print the answer:

const plantNeedsWater = day => day === 'Wednesday' ? console.log('water') : console.log('no water');

but nothing happens. Please advise how to do that?

[vic-st]

Did you call plantNeedsWater?

[digitalmaster95902]

I dind’t, thanks

const plantNeedsWater = day => day === 'Wednesday' ? console.log('water') : console.log('no water');
plantNeedsWater('Wednesday'); // returns water

[markholley]

At this point in my learning, I vastly prefer the longhand way of writing functions.

[mtf]

Preference is subjective. Programming is not about subjectivity, but objectivity. By having a preference we end up closing the book on possible ways to simplify a program and better manage memory and resources.

[markholley]

You’re both correct and infuriating.

[dev0403120509]

Concise arow function seems to work for IF functions.
Example:
userInput2.toLowerCase() === ‘rock’? userInput2+“answer” : “Try again”;
How about when function has 2 more else if parameters ?

[vic-st]

Hey @dev0403120509!

Here’s how:

1 == 2 ? 2+2 : 3
-> 3

That’s just a simple if/else conditional. To make it longer, you do this:

1 == 2 ? 2+12 : 2==2 ? 2+21 : 3+5
  ^       ^      ^      ^      ^
 If     do this  if  do this  else
-> 23     

[mtf]

@dev0403120509

userInput2.toLowerCase() === ‘rock’? userInput2+“answer” : “Try again”;

We need to clarify that this is not a function, but a ternary expression.

condition ? value/action if true : default

As Steven has shown above, nested conditions are written into the default slot.

We should also note that if a value is being assigned then we need a variable to receive it.

a = Math.floor(Math.random() * 10 + 1);
b = a < 5 ? -1 : a > 5 ? 1 : 0;
            ---         --- ---   => values
    -----        -----            => conditions
const f = x => x + 5;
const g = x => x - 5;

console.log(a < 5 ? f(a) : a > 5 ? g(a) : a);
                    ----           ----   => action returns value

[mtf]

Here’s where it gets interesting…

const f = x => x + 5;
const g = x => x - 5;
const h = x => x;

console.log((a < 5 ? f : a > 5 ? g : h)(a));
                    ___         ___ ___       => reference
                                       ---    => invocation

console.log(a * b)  // `b` from above

There is some fun to be had running this sequence repeatedly. Haven’t done it, yet, myself, but that is in the offing.

[jessypinkman1234]

Okay, I’m a bit confused right now. I started this exercise by writing this exact code:

const plantNeedsWater = day => day === 'Wednesday' ? true : false;

But it wasn’t correct apparently since it kept telling me to remove parentheses around the word day.

After reading this whole forum and not finding an answer, I went on and asked codecademy to give me the answer. After clicking the button “give me answer” it gave me this code:

const plantNeedsWater = day => day === 'Wednesday' ? true : false;

Which is the exact same code I’ve wrote before. Is this just a bug in codecademy?

[vic-st]

Hi @jessypinkman1234, welcome to the forums!

As long as your code was exactly the same as the solution, yes that would be a bug. I would recommend submitting a bug report with the same info you posted to the forums.