s method
获取 value 转 string
Implementation
String s(String key, {String defaultValue = '', bool showLog = true}) {
if (!containsKey(key)) {
_log('当前map不存在 key:[$key]', showLog);
return defaultValue;
}
final value = this[key];
if (value is String) return value;
if (value == null) {
_log('[$key]的值为 null', showLog);
return defaultValue;
}
_log('${value.runtimeType} [$key]=$value => String:$value', showLog);
return value.toString();
}