Yes.

Finding the LCA is a well known problem. This probably made most early-solvers vote kyu 6. If you want even more of a challenge, there's this kata waiting for you :)

We cannot help since you provide no information.

The point is this:

Note: Your function should modify the input rather than creating a new array.

Because you try to apply map to something that is null, and this is incorrect in (I guess) JavaScript.

Thanks! I wouldn't be able to solve if I hadn't read your comment.

All of the categories have to either be unique within their set or the same.

In JS, like in most languages (Python is an exception), concatenating comparisons does not work.
Well, it works (in JS at least, in Rust for example you would get an error from the compiler) but does not do what you expect: the expression is evaluated from left to right this way:

• first: q[0] + sq[1] + sq[2] == sq[3] + sq[4] + sq[5] : becomes true or false, which are equivalent to 1 or 0 respectively.
• then: if true, it evaluates 1 == sq[6] + sq[7] + sq[8], if false it evaluates 0 == sq[6] + sq[7] + sq[8], etc.

Mmmmmmm, yes...?

this is the test:

test.assert_equals(is_kiss('Joe is having no fun'), "Keep It Simple Stupid")

So, you probably saw the result from a different test. (The log appearts above the test result)

Also, when you post code, use proper code markdown and click the spoiler tag. (I had to add that to hide your code)

how some numbers require more than one keystroke

Take for example, the key with5jkl on it: it has 4 things you might want to use, but you can't just type the same thing to get each of them. So you just press once for 5, but you have to press twice to get a j, if you want k you press three times, and you need to press four times for that same key to produce the letter l.

Yes, you only have to apply string manipulation and if statements.

console.log works (make sure it's the first line in your code), and what you should return is stated in the kata description, that array without the last element.

There is code written for you that doesn't work as one can think it should, your work is figuring out why.