If you want to match literal r and literal n then you should use the following:

value = value.replace(/(?:[rn])+/g, );

You might think that matching literal r and n with [\r\n] is the right way to do it and it is a bit confusing but it won't work and here is why:

Remember that in character classes, each single character represents a single letter or symbol, it doesn't represent a sequence of characters, it is just a set of characters.

So the character class [\r\n] actually matches the literal characters , r and n as separate letters and not as sequences.

Edit: If you want to replace all carriage returns r, newlines n and also literal r and 'n` then you could use:

value = value.replace(/(?:[rn]|[rn]+)+/g, );

About (?:) it means a non-capturing group, because by default when you put something into a usual group () then it gets captured into a numbered variable that you can use elsewhere inside the regular expression itself, or latter in the matches array.

(?:) prevents capturing the value and causes less overhead than (), for more info see this article.