28 lines
1,022 B
Dart
28 lines
1,022 B
Dart
// Copyright (c) 2021, the Dart project authors. Please see the AUTHORS file
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// for details. All rights reserved. Use of this source code is governed by a
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// BSD-style license that can be found in the LICENSE file.
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// Read the file, spawn an isolate, send the file contents to the spawned
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// isolate, and wait for the parsed JSON.
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import 'dart:async';
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import 'dart:convert';
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import 'dart:io';
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import 'dart:isolate';
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const filename = 'json_01.json';
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Future<void> main() async {
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// Read and parse JSON data in a new isolate,
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// then store the returned Dart representation.
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final jsonData = await Isolate.run(() => _readAndParseJson(filename));
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print('Received JSON with ${jsonData.length} keys');
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}
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/// Reads the contents of the file with [filename],
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/// decodes the JSON, and returns the result.
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Future<Map<String, dynamic>> _readAndParseJson(String filename) async {
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final fileData = await File(filename).readAsString();
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final jsonData = jsonDecode(fileData) as Map<String, dynamic>;
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return jsonData;
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}
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