javascript - Regex: Allow all characters except four, restriction including underscore

Question

I am not very familiar with regex.

I am trying to implement some restrictions on input. I want to allow all numbers and characters, with special characters like ~"$#*@ etc. except these 4: & ' % _.

I tried like:

/[a-zA-Z0-9-!@#$^*)(+=.-~"]/

But it is not restricting the _ underscore. How can I restrict underscore, and is there any best way to allow all except 4 without writing all symbols in regex?

Answer 1

The issue is that your range .-~ (index 46-126) includes underscore (index 95). So you can either figure out what chars are 46-94 and 96-126 or use a lookahead to omit the undesired chars:

(?=[^&'%_])[a-zA-Z0-9-!@#$^*)(+=.-~"]

https://regex101.com/r/rV0gxb/1

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You can also negate like this is it's easier to read:

(?![&'%_])[a-zA-Z0-9-!@#$^*)(+=.-~"]