isBase64 function

bool isBase64(
  1. String input
)

check if a string input is base64 encoded

Implementation

bool isBase64(String input) {
  if (input != null && input.length % 4 != 0 || _regExp.hasMatch(input)) {
    return false;
  }
  var firstPaddingChar = input.indexOf("=");
  return firstPaddingChar == -1 ||
      firstPaddingChar == input.length - 1 ||
      (firstPaddingChar == input.length - 2 && input[input.length - 1] == '=');
}