Delve into building a GraphQL endpoint with Deno, compare technologies, configure queries, and integrate PostgresSQL and MongoDB databases to create a secure, high-performing application.

deno.tar.gz

Deno version

Deno run

deno_run_application

deno_run_db

deno_run_application_server_ts_file

docker-deno

Deno is a modern and secure runtime for JavaScript. It was created by the same team that created Node.js. Deno offers better performance, security, and simplicity than any other JavaScript runtime.

In this course, you will start by understanding the different technologies used in Deno, such as Typescript. You will compare these technologies with JavaScript and GraphQL as well as learn their terminologies. Then, you will create your own endpoint with Deno and configure queries and mutations in it. Next, you will explore two different databases with Deno: first, you’ll learn how to set up an SQL database using PostgresSQL and then how to configure a NoSQL database using MongoDB to store documents and collections of on-demand data. Finally, you’ll put everything together to have a fully functioning GraphQL endpoint made with Deno and backed by PostgreSQL and MongoDB. 

After this course, you’ll be able to create a Deno application and a GraphQL endpoint while having a database of your choice to store data.

Building a GraphQL Endpoint with Deno

To solve this challenge, we need three essential steps. Let’s take a look at them below.


# Step 1: Establishing a MongoDB connection

First, we need to establish the MongoDB connection:

const app = new Application();

app.use(async (ctx, next) => {
    const start = Date.now();
    await next();
    const ms = Date.now() - start;
    ctx.response.headers.set("X-Response-Time", `${ms}ms`);
});

const client = new MongoClient();

// Create connection object
await client.connect("mongodb://localhost:27017");

## Explanation

* **Lines 1–8:** We create and configure a new instance of a Deno application.

* **Line 10:** We create a new MongoDB client instance.

* **Line 13:** We connect to MongoDB.

# Step 2: define MongoDB schema

Next, we need to define the schema and access the MongoDB collections:

Go over the solution for the Mongo and Deno challenge.

Introduction to Deno, TypeScript, and GraphQL

Creating a Basic GraphQL Endpoint

Databases and Deno

SQL: Postgres and Deno

NoSQL: Mongo and Deno

Wrapping Up

Appendix

Solution: Mongo and Deno