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Comment by bendiksolheim | Hacker News Reader

That is an interesting way of seeing it. I’m not saying I disagree with the rationale, but I find it weird that a function which promises to do something needs a specially modified version of its input _not_ throw an exception. That does not sound like a good API design at all.

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This feels like thinking about it the wrong way round: if you want to use regular expressions, use `.replace()`, which has full regex support and always has. There is no need to ever use `replaceAll` with regular expressions. In fact, you'd just be mudding the waters by using a function that implies "all" in combination with a regex that implies "single" (if you don't specify a `g` flag, as per regex convention).

However, if you just want to replace plain strings, `.replaceAll()` actually gives you a fundamentally better API: you can now use `str.replace(s,r)` for single replace, and the intuitive companion function `str.replaceAll(s,r)` for all-instances replace. No "learning/knowing regexp" required just to replace some plain text.

If there is no need in using replaceAll() with regexes, why would it even support it?

I agree that only replacing the first occurrence is the wrong solution. That would be surprising. The only correct solution to this is in my opinion auto-g-ing the regular expression, no matter how unusual that is. There is no way you would write replaceAll() as a mistake when you actually just meant replace().

Mostly to keep the signature for replaceAll in line with replace. You _can_ call it with a regex, but then you'll have to make sure it's a regex that uses the correct syntax for "replace-all" behaviour. If you don't, now you're doing something so weird that an error is the only appropriate response.

<<There is no way you would write replaceAll() as a mistake when you actually just meant replace(). >>

Have you ever reviewed the daily work of colleagues or contributors who haven't used JS day in day for the last 2 years? That's exactly the kind of mistake that happens _all_ the time. And people new to JS are more than happy to reach for regex well before there's a good reason to use them.

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