With Audit Log (proto)

with-audit-log.js

/* tl;dr of the problem 
 - We have a funtion that updates objects and produces two values [updates, auditLogRecord]. 
 Let's call it "applyChangesWithAuditLog"
 - We need to use this function in the context of another function (let's call it "update") and that another function should not be
 aware of the fact that that auditLogRecord's are being produced and collected.
 - When function "update" is executed, we want to collect all auditLogRecords that originated from calls 
 to "applyChangesWithAuditLog" inside "update" function. 
 - Then we want to save all collected auditLog items to DB.
 
 Code below achieves this by building a functional wrapper.
*/

const updateFunc = ({ updateWithAuditLog }) => {};

const createAuditLogCollector = (
  auditLogProducingFunction,
  auditLogContainer = createContainer(),
) => ({
  func: (...args) => {
    {
      const { updates, auditLogRecord } = auditLogProducingFunction(...args);
      auditLogContainer.add(auditLogRecord);
      return updates;
    }
  },
  getCollectedAuditRecords: auditLogContainer.getAll,
  addRecord: auditLogContainer.add,
});

const withAuditLog = updateFunc => auditLog => ({
  func: updateFunc(auditLog.func),
  getCollectedAuditRecords: auditLog.getCollectedAuditRecords,
  addRecord: auditLog.add,
}

const saveAuditLogAfterExecution = createAuditLogRecordsCommand => 
  ({ getCollectedAuditRecords, func }) => 
    async (...args) => {
      const results = await func(...args);
      await createAuditLogRecordsCommand(auditLog.getCollectedAuditRecords());

      return results;
    };

const auditLogCollector = (createAuditLogRecordsCommand, auditLogProducingFunction) => 
  updateFunc => R.pipe(
    createAuditLogCollector,
    withAuditLog(updateFunc),
    saveAuditLogAfterExecution(createAuditLogRecordsCommand)
  )(auditLogProducingFunction)


// auditLog.foo() => updates (+ internal collect)
// auditLog.getCollectedItems()

function stepFactory() {
  const withAuditLog = auditLogCollector(createAuditLogRecordsCommand, auditLogProducingFunction);

  return {
    updateAsUser: withAuditLog(updateAsUser),
  };
}