Javascript regex pattern to match for Function keys from F1-F12 using pattern test function

I tried below but gives false as output, excepted is true

let text = "F11";
let pattern = /^[F][1-12]$/;
let result = pattern.test(text); console.log(result);

CodePudding user response：

This regular expression matches F1-F12: /^F[1-9](?:(?<=1)(?:0|1|2))?$/:

let re = /^F[1-9](?:(?<=1)(?:0|1|2))?$/;

for (var i = 0; i < 16; i  ){
  let text = `F${i}`;
  console.log(`${text}: ${re.test(text)}`);
}

To break it down:

• ^ matches the start of input; it will only match if it is at the beginning
• F matches a literal 'F'
• [1-9] matches a character between 1 and 9
• (?:(?<=1)(?:0|1|2)) is where it matches 11 and 12
  • (?<=1)(?:0|1|2)) is a lookbehind assertion: it will only match the second part if the first is true
    • (?:0|1|2) matches the 0, 1, or 2 for the 10-12