handle-patch.js

// eslint-disable-next-line no-unused-vars
module.exports = function(options = {}) {
  // Return the actual hook.
  return async context => {
  // relationRecords  are array of data
  // e.g: Array<Comments> || Array<Likes> which sequelize will not handle in a patch request
  const { id, data: { relationRecords } } = context;
  const service1 = context.app.service('relation1Service');
  await removeOldData(service1, +id);
  await addNewData(service1, +id, relationRecords);
  return context;
  };
};


// m:n relation
const removeOldData = async (service, fk_id) =>
  service.remove(null, { query: { fk_id } });
  
  
// m:n relation
const addNewData = async (service, fk_id, arrayOfIds) =>
  service.create(
    arrayOfIds.map(({ fk2_id }) => ({ fk2_id, fk_id }))
  );