code: function buildSchema(models, typeMap) {
    let type;
  
    var _models$map$reduce = models.map(model => {
      type = typeMap[model.modelName];
      return {
        query: (0, _buildQuery2.default)(model, type),
        mutation: (0, _buildMutation2.default)(model, type)
      };
    }).reduce((fields, modelField) => {
      fields.query = (0, _assign2.default)({}, fields.query, modelField.query);
      fields.mutation = (0, _assign2.default)({}, fields.mutation, modelField.mutation);
      return fields;
    }, { query: {}, mutation: {} });
  
    const query = _models$map$reduce.query;
    const mutation = _models$map$reduce.mutation;
  
  
    return {
      query: query,
      mutation: mutation
    };
  }
docs: Build graphql CRUD schema based on models and types
  @params
  - models {Array} mongoose models
  - typeMap {Object} map of model and corresponding graphql type
  @return
  - grapqhl schema which has query and mutation