I can assign any number to any word. And it would be a solution. But it would not, in fact, be YOUR solution.
And that's the problem: You did not give a specific value format to follow.

The check is for blank spaces because

 will save all your white-space. aas well as the css-style { white-space: pre; }
Essentially: it's implementation use case.

For those having the trouble of weird justification errors; Make sure you read the instructions thoroughly. They throw some curveballs in there. XD

No spoilers but; that error is directed towards the line it's on. Re-read the instructions, because there's a case you're missing.

I enjoyed the simplicity of this kata. I do however think that more should've been hidden (if possible, i haven't written a kata yet, so i don' tknow the feasibility.)

Something like: "There is a bomb defined somewhere, figure out where to find and diffuse it."

And instead of giving us the functions, we have to find them and call the disable with correct key, or we lose.

The current description pretty much gives us all the answers.

What does each letter/word/space/position have for a value?
Your expectations for what exact value you want returned is very poorly defined.