Converts a string to snake case.

Use String.replaceAllMapped() to break the string into words and String.toLowerCase() to convert each one to lowercase, using a RegExp.
Use String.replaceAll() to replace invalid separator characters (- and spaces) with underscores.

代码实现

String toSnakeCase(String str) {
  return str
      .replaceAllMapped(
          RegExp(
            r'[A-Z]{2,}(?=[A-Z][a-z]+[0-9]*|\b)|[A-Z]?[a-z]+[0-9]*|[A-Z]|[0-9]+'),
          (Match m) => "${m[0].toLowerCase()}")
      .replaceAll(RegExp(r'(-|\s)+'), '_');
}

使用样例

toSnakeCase('camelCase'); // 'camel_case'
toSnakeCase('some text'); // 'some_text'
toSnakeCase('some-mixed_string With spaces_underscores-and-hyphens'); // 'some_mixed_string_with_spaces_underscores_and_hyphens'