mapbox4dart

Pure Dart codec and object model for Mapbox GL Style JSON (v8). Reads and writes Mapbox styles with full roundtrip preservation of unknown fields.

Part of the mapstyler ecosystem.

Features

• MapboxStyleCodec — reads and writes Mapbox GL Style JSON v8.
• Typed object model — MapboxStyle, MapboxLayer, MapboxSource with immutable classes.
• Unknown field preservation — unknown root/layer/source fields survive roundtrip via extra maps.
• Forward-compatible — unknown layer and source types preserved as unknown + rawType.
• Color normalization — hex, rgb(), rgba(), hsl(), hsla(), 140+ CSS named colors → #rrggbb.
• Version validation — rejects non-v8 styles with clear error messages.

Pure Dart — no Flutter dependency. No dependencies beyond dart:convert.

Usage

import 'package:mapbox4dart/mapbox4dart.dart';

const codec = MapboxStyleCodec();

// Read
final result = codec.readString(mapboxJson);
if (result case ReadMapboxSuccess(:final output)) {
  print('${output.name}: ${output.layers.length} layers');
  for (final layer in output.layers) {
    print('  ${layer.id}: ${layer.type}');
  }
}

// Write
final writeResult = codec.writeString(style);
if (writeResult case WriteMapboxSuccess(:final output)) {
  print(output); // JSON string
}

Color normalization

normalizeColor('rgba(255, 0, 0, 0.5)');  // → (hex: '#ff0000', opacity: 0.5)
normalizeColor('#f00');                    // → (hex: '#ff0000', opacity: null)
normalizeColor('hsl(120, 100%, 50%)');     // → (hex: '#00ff00', opacity: null)
normalizeColor('steelblue');               // → (hex: '#4682b4', opacity: null)

License

MIT — see LICENSE.