Hey Everyone,

In this article, we will learn about how we can perform CRUD operations in Node.js using DynamoDB.

What is DynamoDB?

DynamoDB is a NoSQL database offered by Amazon Web Services (AWS). It is a fully managed, serverless, key-value NoSQL database designed to run high-performance applications at any scale.DynamoDB offers built-in security, continuous backups, in-memory caching, and data import and export tools.

Let’s start by creating a node application and installing dependencies.

Create a folder and name it CRUD With DynamoDB. Open the folder with Visual Studio Code. Once inside the VS Code, open the terminal.

Create a package.json file by running:

npm init -y

Once created, Execute the following command to install express, aws-sdk dependencies in your node js app:

npm i express aws-sdk

Now we have to create a table from the AWS DynamoDB console at https://console.aws.amazon.com/dynamodb/.

Click on the create table button and enter the table name and partition key as shown below image and click on the create table button.

Also, you can create a table using the below code:

var AWS = require("aws-sdk");
AWS.config.update({
  region: "us-east-1",
  endpoint: "http://localhost:7051"
});

var client = new AWS.DynamoDB();
var documentClient = new AWS.DynamoDB.DocumentClient();
var tableName = "user";

var params = {
    TableName: tableName,
    KeySchema: [
        { AttributeName: "id", KeyType: "HASH"},  //Partition key
    ],
    AttributeDefinitions: [
        { AttributeName: "id", AttributeType: "S" }
    ]
};

client.createTable(params, function(tableErr, tableData) {
    if (tableErr) {
        console.error("Error JSON:", JSON.stringify(tableErr, null, 2));
    } else {
        console.log("Created table successfully!");
    }
});

Now create an index.js file, So go to your app root directory and create it and put the below code inside it:

const express = require("express");
const app = express();
const port = 7051;
const userRoute = require("./userRoute");

app.use(express.json());
app.use("/", userRoute);

app.listen(port, () => {
    console.log("port is running at new : ", port);
});

Create an userRoute.js file in your root directory and put the below code inside it:

const express = require("express");
const router = express.Router();
const AWS = require('aws-sdk');
const { v4: uuid_v4 } = require('uuid');
AWS.config.update({
    region: "us-east-1"
});
const dynodata = new AWS.DynamoDB.DocumentClient();

router.get("/user", async (req, res) => {
    var params = {
        TableName: "user"
    };
    dyno = await dynodata.scan(params).promise();
    res.json({ message: "User get successfully", dyno });
});

router.post("/user", async (req, res) => {
    if (!(req.body.username && req.body.age && req.body.email)) {
        return res.json("Enter name, age and email....");
    }
    const reEmail = /^(([^<>()[\]\.,;:\s@\"]+(\.[^<>()[\]\.,;:\s@\"]+)*)|(\".+\"))@(([^<>()[\]\.,;:\s@\"]+\.)+[^<>()[\]\.,;:\s@\"]{2,})$/i;
    if (!reEmail.test(req.body.email)) {
        return res.json(401, {
            message: "Please enter a valid email",
        });
    }
    let dynoEmail = await getData("email", req.body.email.toLowerCase().trim());
    if (dynoEmail.Items.length != 0) {
        return res.json(401, {
            message: "Email already exists in our database. please choose a different email address"
        })
    }
    var data = req.body;
    data.id = uuid_v4()
    const params = {
        TableName: "user",
        Item: data
    }
    return await dynodata.put(params).promise().then(() => {
        res.json({ message: "User created successfully", data });
    }
        , error => {
            console.error('There is an error saving user: ', error)
        })
});

router.put("/user/:userId", async (req, res) => {
    const reEmail = /^(([^<>()[\]\.,;:\s@\"]+(\.[^<>()[\]\.,;:\s@\"]+)*)|(\".+\"))@(([^<>()[\]\.,;:\s@\"]+\.)+[^<>()[\]\.,;:\s@\"]{2,})$/i;
    if (!reEmail.test(req.body.email)) {
        return res.json(401, {
            message: "Please enter a valid email",
        });
    }
    var jobParams = {
        TableName: "user",
        Key: {
            id: req.params.userId,
        },
        UpdateExpression: "set email = :e,username =:un, age=:g",
        ExpressionAttributeValues: { ":e": req.body.email, ":un": req.body.username, ":g": req.body.age },
        ReturnValues: "UPDATED_NEW",
    };
    let dyno = await dynodata.update(jobParams).promise();
    res.json({ message: "User updated successfully", dyno });
})

router.delete("/user/:userId", async (req, res) => {
    let params = {
        TableName: "user",
        Key: { id: req.params.userId },
    };
    let dyno = await dynodata.delete(params).promise();
    return res.json(200, { message: "User is deleted" })
});
let getData = async (key1, value) => {
    const params = {
        TableName: "user"
    }
    if (key1 == "email") {
        params.FilterExpression = `#email = :value`;
        params.ExpressionAttributeNames = { "#email": "email" }
        params.ExpressionAttributeValues = { ":value": value }

    }
    db = await dynodata.scan(params).promise();
    return db;
}
module.exports = router;