I try make regular expression for one letter Z and 12 digits.
event.target.value = event.target.value.replace(/[^Z{1}+(\d{12})]/, '');
It is necessary for me that in the input field it was possible to enter one letter Z and then 12 digits only.
Please help me.
The regexp is
/^Z\d{12}$/
^ matches the beginning of the stringZ matches the initial Z. There's no need for {1} since patterns always match exactly one time unless quantified.\d{12} matches exactly 12 digits$ matches the end of the stringconst regex = /^Z\d{12}$/;
console.log(regex.test('Z123456789012')); // true
console.log(regex.test('X123456789012')); // false - begins with wrong letter
console.log(regex.test('Z1234567890')); // false - <12 digits
console.log(regex.test('Z123456A89012')); // false - letter mixed into digits
console.log(regex.test('Z123456789012345')); // false - >12 digits