createFromJsonArg function

Implementation

Expression createFromJsonArg(ServerType type, {required Expression access}) {
  Expression mappedAccess(Expression variable) {
    return refer(
      (Map).name,
    ).newInstanceNamed('from', [variable.asA(refer((Map).name))]);
  }

  if (!type.isNullable) {
    return refer(
      type.nonNullName,
    ).property('fromJson').call([mappedAccess(access)]);
  }

  return createSwitchPattern(access, {
    declareFinal('data', type: refer((Map).name)): refer(
      type.nonNullName,
    ).property('fromJson').call([mappedAccess(refer('data'))]),
    const Code('_'): switch (type.isNullable) {
      true => literalNull,
      false => refer('ArgumentError').newInstance([
        literalString('Cannot convert non-Map value to ${type.name}'),
      ]),
    },
  });
}