Create Strings Using Template Literals?

Tell us what’s happening:
My solution is below. This should work but FCC is saying that “resultDisplayArray is the desired output.” I am returning resultDisplayArray… what’s happening here?

Your code so far

const result = {
 success: ["max-length", "no-amd", "prefer-arrow-functions"],
 failure: ["no-var", "var-on-top", "linebreak"],
 skipped: ["id-blacklist", "no-dup-keys"]
function makeList(arr) {
 "use strict";

 // change code below this line
 const resultDisplayArray = => {`<li class="text-warning">${el}</li>`});
 // change code above this line

 return resultDisplayArray;
* makeList(result.failure) should return:
* [ `<li class="text-warning">no-var</li>`,
*   `<li class="text-warning">var-on-top</li>`,
*   `<li class="text-warning">linebreak</li>` ]
const resultDisplayArray = makeList(result.failure);

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Challenge: Create Strings using Template Literals

Link to the challenge:

if you use the { graph brackets there is no implicit return. the callback is not returning anything. if you want to use implicit return it is el => valué, or you need to use the return keyword

Your resultDisplayArray does not contain the correct value. With a fat arrow function you can omit the return statement if you don’t provide a function block. However, if you use curly braces ({}) then their contents will be evaluated as a function and a return statement needs to be explicit. Your map callback function doesn’t return a value, so you just have an array of undefined.

I thought {} were required in arrow functions to denote the body of the function though…

But then that function needs a return statement.

Hmmm that’s interesting. It works without the curly braces. Why do arrow functions work that way? When would I want to use curly braces in an arrow function (thus requiring an explicit return) versus no curly braces and no explicit return?

for implicit return you don’t need curly braces
you can use implicit return if the only line of your function is a return statement

otherwise you need to use the curly braces for the function block, and then you need to use the return keyword to return something

Oh I see. That makes sense.

So basically, if your arrow function needs more than one concise statement to… well, function then you would use curly braces and a return. But if it’s a short one-liner then the braces (and the return) are most likely unnecessary.

1 Like

there is no “most likely”, it’s how it works: implicit return can be used only if your function is a oneliner. if you use curly braces to define the function block and you don’t use the return keyword your function returns undefined

Gotcha - thank you very much! I am learning a lot!

The “most likely” stems from my lack of confidence at this early stage in my learning process. I’ve got a nasty case of imposter syndrome that I have to fight off constantly.