isCharDigit function

bool isCharDigit(
  1. String char
)

Returns true if char represents a digit, false otherwise.

This function checks whether the input string is not empty and whether its first character is a digit (i.e., has a Unicode code point between the code points of '0' and '9').

If the input string satisfies this condition, the function returns true. Otherwise, it returns false.

Implementation

bool isCharDigit(String char) {
  if (char.isEmpty) return false;

  final firstCodePoint = char.codeUnitAt(0);

  return (firstCodePoint >= '0'.codeUnitAt(0)) &&
      (firstCodePoint <= '9'.codeUnitAt(0));
}