How to check if string has special character in JS?

Question

Trying to write logic if string has special character / or % replace that from the string so first i have check if special character is part of the string then replace it else return the text that was passed. E.g Tylenol 2/ml or Tylenol .05% output should be Tylenol 2ml and Tylenol .05. hasChar always return false what is correct approach or regex to use ?

main.js

function removeSpecialyCharacter(txt){
  let str = txt;
 if(hasChar(txt)){
   str = txt.replace(/[^a-zA-Z ]/g, "");
 }
  return str;
}

function hasChar(str){
 return !/[~`!#$%\^&*+=\-\[\]\\';,/{}|\\":<>\?]/g.test(str);
}

Try escaping `/` in your `hasChar` regex. Also, `\\'` and `\\"` are `\`, `'`, and `"` characters, not sure that what you intended. Also, you have two different regex patterns to accomplish the same thing, just use one and always call the replace - no point in checking, then replacing, will still have the same outcome (just won't replace anything since no matches). — ctwheels, Nov 18 '19 at 20:03
Is it really necessary that you know the string contains any of those characters before trying the `.replace()`? If you attempt a `.replace()` on the string and it *doesn't* have special characters, the string will simply not change. — Tyler Roper, Nov 18 '19 at 20:03
@TylerRoper ok that make sense so you are saying i dont need to have a check for special character replace will only apply if it has special character — aftab, Nov 18 '19 at 20:08
@aftab Another thing to note is that your replace function will replace your digits since you've specified any non-alphabet and not space character `[^a-zA-z ]`. You should probably only specify what you do want to remove (and include a list of all character or a group name for the character you want to remove in your question - for example, is it all punctuation characters?). Or maybe there's a list of character you want to keep (is it all alphanumeric characters and `.`? — ctwheels, Nov 18 '19 at 20:12
`str = txt.replace(/[^a-zA-Z ]/g, "");`with this it is also removing the space and digits — aftab, Nov 18 '19 at 20:13
@TylerRoper i have specified in questions only `/` and `%` should be removed — aftab, Nov 18 '19 at 20:15
@aftab then just use `str.replace(/[%\/]/g, '')`. It'll only replace those chars if they're in the string. — ctwheels, Nov 18 '19 at 20:19
@aftab I guarantee you that's the correct answer. Tried and tested. See [here](https://tio.run/##y0osSyxOLsosKNEts/j/v7ikKDMvvVjBViFaPaQyJzUvP0fBSD83R10HztUzMFVVj@VKyy9S0ChWyE9TgOrRVKjmUlCoAGot1itKLchJTE7V0I9WjdGP1U/XUVBX1wTKJufnFefnpOrl5KdrVGhy1f7/DwA) — ctwheels, Nov 18 '19 at 20:27
@aftab Make sure you're setting `str` to the result. `str.replace()` does not modify `str` (strings are immutable). You need to do `str = str.replace()`. (Also, I think all of your replies are meant for *ctwheels*) — Tyler Roper, Nov 18 '19 at 20:28

How to check if string has special character in JS?

0 Answers0