Capitalizes the first letter of a string.

Use String.toUpperCase() to capitalize first letter and String.toLowerCase() to convert the rest of the string to lowercase, if necessary.
Omit the optional parameter, lowerRest, to keep the rest of the string intact, or set it to true to convert to lowercase.

代码实现

String capitalize(String str, {bool lowerRest = false}) {
  return str[0].toUpperCase() +
      (lowerRest ? str.substring(1).toLowerCase() : str.substring(1));
}

使用样例

capitalize('fooBar'); // 'FooBar'
capitalize('fooBar', lowerRest: true); // 'Foobar'