numberConvert method

@override num? numberConvert(dynamic x)

Implementation

@override
num? numberConvert(dynamic x) {
  if (x is num) {
    return (x is double) ? x : x.toDouble();
  } else if (x is bool) {
    return x ? 1.0 : 0.0;
  } else if (x is String) {
    try {
      return double.parse(x); // use javascript semantics: numbers are doubles
    } catch (e) {
      // ignore and return null
    }
  }

  return null;
}