Seems tests are broken for js:

typeError: a.add(...).equals is not a function

Also, throwing an error is not supported here for JS we can throw new Error() but its ignored by the tests

This is a rather confusing challenge, its not at all clear as to the entire parameters as the tests, dont provide any extra info apart from random failures.

OP fixed it

Works in node console returning false for over 140, but fails tests here

I dont have an example, as I mentioned previously these are merely rhetorical queries, not examples, I suggest it remains the same for now, as there are a number of comments here which are abvle to provide clarity.

Whilst I thank you for that edicational aside, I feel you have somewhat failed to grasp the scope of my confusion. It was nothing to do with any such pedagogical issues, it was entiely a communicative and semantic problem. The challenge problem was clear and precise, however, again in my opinion, I felt that the approach was rather obscured in the description, this is the core of my issue, and makes no assumptions about creativity or any such facet, merely a slight obfuscation due to language.

I have gone through te examples ans solutions, having forefitted the challenge, and now understand it better. My issue was not personal in the slightest, though you appear to have taken some issue with it form the rather defensive nature of your reply. This was certainly not my intention. I merely provided an opinion on my reading of the challenge.

OK, thank you

No need to apologize, this is my confusion, it may well be clear for others!

For me as a native English speaker, the description is clear enough to an extent. However, the examples are where the confusion lies, For example, you have provided this:

"Given a sequence of one or more 'consecutive natural numbers' concatenated into a string, return the smallest possible first number in the sequence."

"91011" -> [9, 10, 11] -> 9

Under which premise is this not [9,0,1,1] as a sequence? Both 1 and 9 are natural numbers with 1 being the smallest. However you have stated "smallest possible first number" Im not sure what you mean here, the smallest natural number or the first natural number of the sequence.

Given:

"121122123" -> [121, 122, 123] -> 121

Its not clear how you are choosing to group these numbers, there is no pattern here why is this not [1,2,1,1,2,2,1,2,3] or [12,11,22,12,3] ?

Of course this is my own confusion here, but I am struggling to follow how the challenge text and the examples fit together. The tests do not really help much in this case either.

Please note these examples are taken from your description, they are not mine

Yes!

The description is very unclear, for many it needs far more details, as it appears there is some alleged grouping of numbers, yet the limits dont give any clear explanation of wat is expected.

5407 to equal 5408 ??
5407 should be 55th century shouldn't it?

This is what the test requires, but its incorrect in reality

1900 should be 20