example:
try{
var user_regex = "/\\b(.*)\\b/gi"; //user typing own regex
//... throw if regex is infinite
var regex = new RegExp(user_regex);
catch(e){
console.error(e);
}
How to prevent this situation?
Thank you, for help.
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DhivinX
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6what do you mean by `infinite` related to a regular expression? – Fabrizio Calderan Feb 28 '20 at 10:03
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Regex in example is executing infinite. See: https://www.regextester.com/?fam=114934 – DhivinX Feb 28 '20 at 10:06
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1It is because the pattern can match an empty string. – Wiktor Stribiżew Feb 28 '20 at 10:07
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User can typing pattern. How to prevent it? – DhivinX Feb 28 '20 at 10:08
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test it over an empty string. if the match is valid refuse the regexp – Fabrizio Calderan Feb 28 '20 at 10:09
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[Doesn't happen on another tester though](https://regex101.com/r/zpFtAC/2) – Sweeper Feb 28 '20 at 10:12
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Ohh, I see. I'll try to do it. – DhivinX Feb 28 '20 at 10:12
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the regex can return an empty string but the empty string doesn't match because of word boundary. `var user_regex=/\b(.*)\b/g; [ user_regex.exec('abc def'), user_regex.exec('abc def'), user_regex.exec('abc def') ];` and will never return null – Nahuel Fouilleul Feb 28 '20 at 10:25