Question

I try to solve the same problem in javascript with regexp mentioned here: Check if string is repetition of an unknown substring

I translated the regex in the first answer to Javascript: ^(.+){2,}$
But it does not work as I expect:

'SingleSingleSingle'.replace(/^(.+){2,}$/m, '$1')  // returns 'e' instead of exptected 'Single'

What am I overlooking?

Answer 1

I currently have no explanation for why it returns e, but . matches any character and .{2,} basically just means “match any two or more characters”.

What you want is to match whatever you captured in the capture group, by using backreferences:

/^(.+)\1+$/m

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I just noticed that this is also what the answer you linked to suggests to use: /(.+)\1+/. The expression is exactly the same, there is nothing you have to change for JavaScript.