handler.js

const AWS = require("aws-sdk");
const express = require("express");
const serverless = require("serverless-http");
const app = express();
const USERS_TABLE = process.env.USERS_TABLE;
const dynamoDbClient = new AWS.DynamoDB.DocumentClient();

app.use(express.json());

app.get("/users/:userId", async function (req, res) {
  userId = req.params.userId;
  try {
    res.status(200).json({ success: 'Hello World' })
  } catch (error) {
    console.log(error);
    res.status(500).json({ error: "Could not retreive user" });
  }
});

app.post("/users", async function (req, res) {
  const { userId, name } = req.body;
  if (typeof userId !== "string") {
    res.status(400).json({ error: '"userId" must be a string' });
  } else if (typeof name !== "string") {
    res.status(400).json({ error: '"name" must be a string' });
  }

  const params = {
    TableName: USERS_TABLE,
    Item: {
      userId: userId,
      name: name,
    },
  };

  try {
    await dynamoDbClient.put(params).promise();
    res.json({ userId, name });
  } catch (error) {
    console.log(error);
    res.status(500).json({ error: "Could not create user" });
  }
});

app.use((req, res, next) => {
  return res.status(404).json({
    error: "Not Found",
  });
});


module.exports.handler = serverless(app);