FAQ: Iterators - Iterator Documentation

This community-built FAQ covers the “Iterator Documentation” exercise from the lesson “Iterators”.

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This exercise can be found in the following Codecademy content:

Web Development

Introduction To JavaScript

FAQs on the exercise Iterator Documentation

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Hi there, could someone tell me, in this line of code:

const interestingWords = words.filter((word) => {return word.length > 5});

what is the function, what is the callback function, what is the method, what are the arguments?
I kind of get it but it makes no sense to me, thanks!

filter is the method used on the array. The callback function is the arrow function – (word) => {return word.length >5} – . This arrow function is passed as an argument to the filter method.

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so does the console not mind the extra un-needed parenthesis here? there was only 1 parameter for each but the template made it seem like you needed 2 :wink: i left the extra parenthesis and didn’t throw an error.

if the function has a single parameter, you can leave the parenthesis ( () ) out, its just a shorthand.

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you call the .every method on interestingWords (not words), which contains words with length greater then 5 given the filter action you did earlier

but its still a bit of a guess from my side, given i can’t get your code to run without making assumptions. if you call every on words, you should get false indeed


Just want to ask a follow up question concerning this assignment:

the array consists of: [‘unique’, ‘uncanny’, ‘pique’, ‘oxymoron’, ‘guise’];

the assignment asks for content of more then 5 chars.
return word.length > 5

but in the array there are 2 words with 5 chars, seeing the ‘=’ is not included why does it still return ‘true’??

Thanks Maarten

i assume it refers to the result of the every method?

well, we have two arrays now: words and interestingWords, you call the .every method on the interestingWords array, which only contains words with more then 5 characters (courtesy to the filter method)


thanks @stetim94,

I was confused, as it does make a new variable were the new array is saved in. Hence the ‘true’ output as, indeed, the words more than 5 chars are in there…


Thanks !

Hi everyone!, could I ask why does .every() & .some() methods require a “return” statement and filter and other methods dont? is it because they return a Boolean?


The two functions take a predicate function, so yes, they will return a boolean. filter returns a list of values that once tested against an expression return true.


Hello there, I’ve been doing the first step

In the code editor, there is an array called words . We want to create a new array of interesting words. The first thing we want to do is check if there are words that are fewer than 6 characters long. There is something missing in the words.some() method call. Fix this method so that true is printed to the console.

So I’ve modified code to this state :

const word1 = (word) => { return word.length < 6; }; console.log(words.some(word1))

And it returns ‘true’, but task didn’t verify it as a solution, why?

It may indeed be correct, as it shows no obvious errors. However, if the pattern above is not recognized, the SCT will not accept it.

Consider that arrow function syntax does have some shortcuts permitted in certain cases.

Single parameter ?  no parens required
Single statement ?  no curly braces or return required.


shortWords = word => word.length < 6;

The above is valid arrow syntax given a single parameter, and only one expression, permitting implicit return.

Let us know if this pattern meets with the SCT’s expectations.

So, I’ve returned to the exercise and tried this, and it still did not meet SCT expectations (tho, I’ve moved on, by solving this with method, that meets expectations). And sorry if I’ve misunderstood something.
const shortWords = word => word.length < 6; console.log(words.some(shortWords))


It always helps to go and look at the lesson. It asks us to use .some

The line I wrote above is missing the method so will obviously not work. It should look something like this,

 console.log(words.some(word => word.length < 6))

which will be True since two of the words are less than 6 characters.

I was able to create the interestingWords, but now as I attempt to call the actual words I end up with an error saying the ‘interestingWords’ is not a function… which to me is… what is wrong here?

const interestingWords = words.filter(word => word.length > 5);

every needs need a callback function just like filter, and interestingWords is not a function.

every documention - MDN

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right… I need to get my head around that… gosh… Thx

What might help is to write a higher order function yourself? You could just write a function to log something:

current value is : 1
current value is : 2
current value is : 3

for example, here is something to help you:

function each(callback, myArray){
   // todo, write logic to execute callback and print value from the array

function myCallBack(elelemt){
    console.log(`the current value is ${element}`);

each is the higher order function here.

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For the first question in the instructions, I have added function with the parameters of word as follows it returns true but will not pass me to the next question, please advise on what, I am doing wrong. I have been stuck for longer than a hour already.

  return word.length < 6;