SimpleCustomConversion constructor

SimpleCustomConversion(Map<dynamic, double> mapConversion, { Map<dynamic, String?>? mapSymbols, int significantFigures = 10, bool removeTrailingZeros = true, bool useScientificNotation = true, dynamic name, })

Class for simple custom conversions. E.g.:

final Map<String, double> conversionMap = {
 'EUR': 1,
 'USD': 1.2271,
 'GBP': 0.9033,
 'JPY': 126.25,
 'CNY': 7.9315,
};
final Map<String, String> mapSymbols = {
 'EUR': '€',
 'USD': '\$',
 'GBP': '₤',
 'JPY': '¥',
 'CNY': '¥',
};
var customConversion = SimpleCustomConversion(conversionMap, mapSymbols: mapSymbols);
customConversion.convert('EUR', 1);
Unit usd = customConversion.getUnit('USD');
print('1€ = ${usd.stringValue}${usd.symbol}');

Implementation

SimpleCustomConversion(this.mapConversion,
    {this.mapSymbols,
    this.significantFigures = 10,
    this.removeTrailingZeros = true,
    this.useScientificNotation = true,
    name}) {
  assert(mapConversion.containsValue(1),
      'One conversion coefficient must be 1, this will considered the base unit');
  if (mapSymbols != null) {
    for (var val in mapConversion.keys) {
      assert(mapSymbols!.keys.contains(val),
          'The key of mapConversion must be the same key of mapSymbols');
    }
  }
  this.name = name;
  size = mapConversion.length;
  var baseUnit = mapConversion.keys.firstWhere(
      (element) => mapConversion[element] == 1); //take the base unit
  List<Node> leafNodes = [];
  mapConversion.forEach((key, value) {
    if (key != baseUnit) {
      //I'm just interested in the relationship between the base unit and the other units.
      leafNodes.add(Node(name: key, coefficientProduct: 1 / value));
    }
  });
  if (mapSymbols == null) {
    mapSymbols = <dynamic, String?>{};
    for (var val in mapConversion.keys) {
      mapSymbols![val] = null;
    }
  }
  Node conversionTree = Node(name: baseUnit, leafNodes: leafNodes);
  _customConversion = CustomConversion(
      conversionTree: conversionTree,
      mapSymbols: mapSymbols!,
      significantFigures: significantFigures,
      removeTrailingZeros: removeTrailingZeros,
      useScientificNotation: useScientificNotation,
      name: name ?? PROPERTY.angle);
}