Dart Requires Chilkat v11.0.0+

Get the Root of a JSON Document

See more JSON Examples

Demonstrates how to get back to the JSON root object from anywhere in the JSON document. This example uses the following JSON document:

{
  "flower": "tulip",
  "abc":
    {
    "x": [
       { "a" : 1 },
       { "b1" : 100, "b2" : 200 },
       { "c" : 3 }
    ],
    "y": 200,
    "z": 200
    }
}

Dart

import 'package:chilkat/chilkat.dart';

void main() {
  final json = CkJsonObject();

  final jsonStr = '{"flower": "tulip","abc":{"x": [{ "a" : 1 },{ "b1" : 100, "b2" : 200 },{ "c" : 3 }],"y": 200,"z": 200}}';

  try {
    json.load(jsonStr);
  } on ChilkatException catch (e) {
    print(e.lastErrorText);
    return;
  }

  // Get the "abc" object.
  final abcObj = CkJsonObject();
  try {
    json.objectOf2('abc', abcObj);
  } on ChilkatException catch (e) {
    print(e.lastErrorText);
    return;
  }

  // Side note: The JSON of a sub-part of the document can be emitted from any JSON object:
  abcObj.emitCompact = false;
  print(abcObj.emit());

  // Navigate to the "x" array
  final xArray = CkJsonArray();
  abcObj.arrayOf2('x', xArray);

  // Navigate to the 2nd object contained within the array.  This contains members b1 and b2
  final bObj = CkJsonObject();
  xArray.objectAt2(1, bObj);

  // Show that we're at "b1/b2".
  // The value of "b1" should be "200"
  print('b2 = ${bObj.intOf('b2')}');

  // Now go back to the JSON doc root:
  final docRoot = CkJsonObject();
  bObj.getDocRoot2(docRoot);

  // We'll skip the null check and assume it's non-null...

  // Pretty-print the JSON doc from the root to show that this is indeed the root.
  docRoot.emitCompact = false;
  print(docRoot.emit());
}