How to use the graphi.graphql.GraphQLObjectType function in graphi

Assert(typeof fieldResolver === 'function', `${resolverName}.${fieldName} resolver must be a function`);

      if (type instanceof graphql.GraphQLScalarType) {
        type[fieldName] = fieldResolver;
        continue;
      }

      if (type instanceof graphql.GraphQLEnumType) {
        const fieldType = type.getValue(fieldName);
        Assert(fieldType, `${resolverName}.${fieldName} enum definition missing from schema`);
        fieldType.value = fieldResolver;
        continue;
      }

      // no need to set resolvers unless we are dealing with a type that needs resolvers
      if (!(type instanceof graphql.GraphQLObjectType) && !(type instanceof graphql.GraphQLInterfaceType)) {
        continue;
      }

      const fields = type.getFields();
      if (!fields) {
        continue;
      }

      fields[fieldName].resolve = fieldResolver;
    }
  }
  return astSchema;
};