isAlphaNumeric function

bool isAlphaNumeric(
  1. String input
)

Checks if the provided character input is alphanumeric (A-Z, a-z, 0-9).

print(isAlphaNumeric('a')); // true
print(isAlphaNumeric('5')); // true
print(isAlphaNumeric('@')); // false
print(isAlphaNumeric('Hello123')); // true
print(isAlphaNumeric('Hello@123'));  // false

Implementation

bool isAlphaNumeric(String input) {
  if (input.length == 1) {
    return isDigit(input) || isAlpha(input);
  } else {
    return input.split('').every((c) => isAlphaNumeric(c));
  }
}