Regular expression to match nothing and anything but not only whitespace string?-CodePudding

I have already found similar question but unfortunately it does not fit to my requirements -> regular expression for anything but an empty string

Question: Is this possible to match with Regex anything or nothing but not string which contains only whitespaces?

String s1 = "";       // -> true
String s2 = "test";   // -> true
String s3 = "  test"; // -> true
String s5 = " ";      // -> false
String s6 = "   ";    // -> false

CodePudding user response：

You can use

^(?!\s $).*

See the regex demo (changed to PCRE and \h to match just horizontal whitespaces for the sake of the demo (\h is not supported in JavaScript regex)).

See a JavaScript snippet showcasing how the regex works:

const trues = ["", "test", "  test"];
const falses = [" ", "\t"];
const regex = /^(?!\s $).*/;
console.log(trues.every(x => regex.test(x)));   // true, all true cases are matched
console.log(falses.every(x => !regex.test(x))); // true, all false cases failed to match

CodePudding user response：

This can solve your issues:

/\s/g