forest-express-sequelize/dist/services/resources-exporter.js

Official Express/Sequelize Liana for Forest

"use strict";

require("core-js/modules/es.array.iterator.js");
require("core-js/modules/es.array.sort.js");
const _ = require('lodash');
const ResourcesGetter = require('./resources-getter');
const HasManyGetter = require('./has-many-getter');
const BATCH_INITIAL_PAGE = 1;
const BATCH_SIZE = 1000;
function ResourcesExporter(model, options, params, association, user) {
  const primaryKeys = _.keys((association || model).primaryKeys);
  params.sort = primaryKeys[0] || 'id';
  params.page = {
    size: BATCH_SIZE
  };
  function getter() {
    if (association) {
      return new HasManyGetter(model, association, options, params, user);
    }
    return new ResourcesGetter(model, options, params, user);
  }
  function retrieveBatch(dataSender, pageNumber) {
    params.page.number = pageNumber;
    return getter().perform().then(function (results) {
      const records = results[0];
      return dataSender(records).then(function () {
        if (records.length === BATCH_SIZE) {
          return retrieveBatch(dataSender, pageNumber + 1);
        }
        return null;
      });
    });
  }
  this.perform = function (dataSender) {
    return retrieveBatch(dataSender, BATCH_INITIAL_PAGE);
  };
}
module.exports = ResourcesExporter;