什么是允许空白或数值的正确正则表达式

Question

I want to validate one variable named "Port" in my JavaScript to accept only either numerical digits or a blank value. I am not sure exactly what regex I can use to satisfy both conditions. Can anyone suggest me logic to use under my if loop to validate this?

Answer 1

If you want to achieve your goal with regexes, you are looking for:

 const regex = /^\\d*$/; console.log(regex.test("")); // true console.log(regex.test("8080")); // true console.log(regex.test("4d54")); // false