app.js

const AWS = require('aws-sdk');
var awsServerlessExpressMiddleware = require('aws-serverless-express/middleware');
var bodyParser = require('body-parser');
var express = require('express');

//（中略）

const userIdPresent = true; 
const partitionKeyName = 'pk';
const partitionKeyType = 'S';
const sortKeyName = 'sk';
const sortKeyType = 'S';

//（中略）

app.get(path + hashKeyPath, function (req, res) {
  var condition = {};
  condition[partitionKeyName] = {
    ComparisonOperator: 'EQ',
  };

  if (userIdPresent && req.apiGateway) {
    condition[partitionKeyName]['AttributeValueList'] = [
      `${userIdPrefix}${req.apiGateway.event.requestContext.identity.cognitoIdentityId}` ||
        UNAUTH,
    ];
  } else {
    try {
      condition[partitionKeyName]['AttributeValueList'] = [
        convertUrlType(
          `${userIdPrefix}${req.params[partitionKeyName]}`,
          partitionKeyType
        ),
      ];
    } catch (err) {
      res.statusCode = 500;
      res.json({ error: 'Wrong column type ' + err });
    }
  }

  let queryParams = {
    TableName: tableName,
    KeyConditions: condition,
  };

  dynamodb.query(queryParams, (err, data) => {
    if (err) {
      res.statusCode = 500;
      res.json({ error: 'Could not load items: ' + err });
    } else {
      const todos = mapDbToTodoModel(data.Items);
      res.json(todos);
    }
  });
});

//（中略）

app.post(path, function (req, res) {
  const item = mapTodoModelToDb(req);
  item[sortKeyName] = `${todoIdPrefix}${getNewId()}`;

  let putItemParams = {
    TableName: tableName,
    Item: item,
  };
  dynamodb.put(putItemParams, (err, data) => {
    if (err) {
      res.statusCode = 500;
      res.json({ error: err, url: req.url, body: req.body });
    } else {
      res.json({ success: 'post call succeed!', url: req.url, data: data });
    }
  });
});

//（以下略）