io-ts-newbie-code.ts

import { Router } from 'express';
import { printCurls } from './curls';
import { modelFactory } from './model';
import { ExceptionResult, FailureResult } from '../../types';
import { CodeCaseAction } from './types';
import * as t from 'io-ts';
import { pipe } from 'fp-ts/lib/pipeable';
import { fold, either } from 'fp-ts/lib/Either';
import { Collection } from 'mongodb';

export const codeCasesFactory = (
  router: Router,
  collection: Collection<unknown>
) => {
  if (process.env.PRINT_CODE_CASE_CURLS) {
    printCurls();
  }

  const model = modelFactory(collection);

  router.post('/api/code-cases/', (req, res) => {
    const rawAction: unknown = req.body;

    const onFailure = (errors: t.Errors): string => {
      const result: FailureResult = {
        status: 'failed',
        type: 'validation_failed'
      };

      // TODO: Only have one res.send
      res.send(result);
      return `Action failed. ${errors.map(error =>
        error.context.map(({ key }) => key).join('.')
      )}`;
    };

    const onSuccess = () => `Action succeeded.`;

    const rawToken = req.headers['x-access-token'];

    pipe(
      either.map(CodeCaseAction.decode(rawAction), async action => {
        const result = await model
          .handleAction(rawToken, action)
          .catch(error => {
            const result: ExceptionResult = {
              status: 'exceptioned',
              type: 'unexpected_error',
              stack: error.stack || new Error().stack
            };
            return result;
          });

        // TODO: Only have one res.send
        res.send(result);
      }),
      // TODO: How should we fold?
      fold(onFailure, onSuccess)
    );
  });

  return {
    model
  };
};