getJsonValue function

Future getJsonValue(dynamic json, String path, dynamic defaultValue)

Retrieves a value from a nested JSON structure based on a provided path.

The json parameter is the JSON object from which to extract the value. The path parameter is a dot-separated string representing the path to the desired value. The defaultValue parameter is returned if the value is not found or if an error occurs.

Returns the value from the JSON structure if found; otherwise, returns the defaultValue. If an error occurs during the process, the defaultValue is returned.

Example usage:

dynamic json = {
  'foo': {
    'bar': [
      {'baz': 'value'}
    ]
  }
};
dynamic result = await getJsonValue(json, 'foo.bar[0].baz', 'default');
print(result); // Output: 'value'

Implementation

Future<dynamic> getJsonValue(
    dynamic json, String path, dynamic defaultValue) async {
  try {
    List<String> pathSplitter = path.split(".");

    dynamic currentValue = json;

    for (String part in pathSplitter) {
      if (currentValue == null) {
        return defaultValue;
      }

      if (part.contains('[') && part.contains(']')) {
        int index1 = part.indexOf('[');
        int index2 = part.indexOf(']');
        int index = int.parse(part.substring(index1 + 1, index2));
        part = part.substring(0, index1);

        if (currentValue is Map<String, dynamic> &&
            currentValue.containsKey(part)) {
          currentValue = currentValue[part];
          if (currentValue is List) {
            currentValue = currentValue[index];
          } else {
            return defaultValue; // If not a list but index is provided, return default
          }
        } else {
          return defaultValue; // If part is not in currentValue or not a map, return default
        }
      } else {
        if (currentValue is Map<String, dynamic> &&
            currentValue.containsKey(part)) {
          currentValue = currentValue[part];
        } else {
          return defaultValue; // If part is not in currentValue or not a map, return default
        }
      }
    }

    return currentValue ?? defaultValue;
  } catch (error) {
    // handle error
    return defaultValue;
  }
}