convertJSObjectToMap function

Map<String, dynamic>? convertJSObjectToMap(dynamic jsObject)

Converts a JavaScript object to a Dart Map.

This function bridges JavaScript interop by extracting properties from a JSObject and creating a corresponding Dart Map<String, dynamic>.

Returns null if jsObject is null or not a JSObject. Throws an exception if the conversion fails due to invalid JavaScript object.

Implementation

Map<String, dynamic>? convertJSObjectToMap(dynamic jsObject) {
  // Handle null input early
  if (jsObject == null) {
    return null;
  }

  // Initialize the result map that will hold our Dart representation
  final resultMap = <String, dynamic>{};

  // Only process if we have a valid JavaScript object
  if (jsObject is! JSObject) {
    return resultMap;
  }

  try {
    // Get the global Object constructor
    final objectConstructor = globalContext['Object'];
    if (objectConstructor == null) {
      return resultMap;
    }

    // Use JavaScript's Object.keys() method to get all property names
    // This returns a JSArray containing all enumerable property keys
    final keysResult = (objectConstructor as JSObject)
        .callMethod('keys'.toJS, jsObject);

    if (keysResult == null || keysResult is! JSArray) {
      return resultMap;
    }

    final keys = keysResult;

    // Get the number of keys (properties) in the JavaScript object
    final lengthProperty = keys.getProperty('length'.toJS);
    if (lengthProperty == null) {
      return resultMap;
    }

    final lengthDartified = lengthProperty.dartify();
    if (lengthDartified is! int) {
      return resultMap;
    }

    final length = lengthDartified;

    // Iterate through each key and extract the corresponding value
    for (var i = 0; i < length; i++) {
      try {
        // Get the key name and convert it to a Dart String
        final keyProperty = keys.getProperty(i.toJS);
        if (keyProperty == null) {
          continue;
        }

        final keyDartified = keyProperty.dartify();
        if (keyDartified == null) {
          continue;
        }

        final key = keyDartified.toString();

        // Get the value for this key and convert it to a Dart type
        // .dartify() handles the conversion from JS types to Dart types
        final valueProperty = jsObject.getProperty(key.toJS);
        final value = valueProperty.dartify();

        // Store the key-value pair in our result map
        resultMap[key] = value;
      } catch (e) {
        // Skip individual properties that fail to convert
        continue;
      }
    }
  } catch (e) {
    // If conversion fails completely, return empty map
    return resultMap;
  }

  // Return the populated map
  return resultMap;
}