Working with YAML

How to:

In Dart, working with YAML typically involves using a third-party library as the language does not include built-in YAML parsing capabilities. A popular choice is the yaml package. To begin, you’ll need to add this package to your pubspec.yaml:

  yaml: ^3.1.0

Remember to run pub get to fetch the package.

Reading YAML

To read a YAML file, first, import the yaml package and then use the loadYaml function:

import 'package:yaml/yaml.dart';
import 'dart:io';

void main() {
  final file = File('config.yaml').readAsStringSync();
  final yamlMap = loadYaml(file);

  print(yamlMap['name']); // Output: John Doe

Assuming your config.yaml file looks like this:

name: John Doe
age: 30

Writing YAML

While the yaml package is great for parsing, it doesn’t support writing YAML. For that, you might need to convert your data to YAML manually or use another package if available. Or, more straightforwardly, manage your data transformations and output them as strings that match YAML syntax:

Map<String, dynamic> data = {
  'name': 'Jane Doe',
  'age': 29,

String toYamlString(Map<String, dynamic> map) {
  String yaml = '';
  map.forEach((key, value) {
    yaml += '$key: $value\n';
  return yaml;

void main() {
  print(toYamlString(data)); // Output: name: Jane Doe
                             //         age: 29

This is a rudimentary approach and might not suit complex data structures or special YAML features. For sophisticated needs, you might have to look for or contribute to a more comprehensive Dart package.