In today’s fast-paced world, efficient delivery tracking systems are essential for businesses to ensure smooth logistics operations. JavaScript and GraphQL are powerful technologies that can be used to build a flexible and scalable delivery tracking system. In this tutorial, we will explore how to use these technologies to create a robust delivery tracking system.

Prerequisites

Before we begin, make sure you have the following installed:

• Node.js
• npm (Node Package Manager)
• Any code editor of your choice

Setting up the Project

To start, let’s set up our project by following these steps:

1. Create a new folder for your project and navigate to it using the command line.
2. Initialize a new Node.js project by running the following command:

   npm init -y
   

3. Install the necessary dependencies by running the following commands:

   npm install express graphql express-graphql
   

Setting up the Server

Now that our project is set up, let’s create the server using Express.js and GraphQL. Follow these steps:

1. Create a new file called server.js and open it in your code editor.
2. Import the required dependencies by adding the following lines at the top of your file:

   const express = require('express');
   const { graphqlHTTP } = require('express-graphql');
   const { buildSchema } = require('graphql');
   

3. Define the GraphQL schema by adding the following code: ```javascript const schema = buildSchema(` type Query { deliveries: [Delivery] }

type Delivery { id: ID! customerName: String destination: String status: String } `);

4. Implement the resolver functions by adding the following code:
```javascript
const root = {
  deliveries: () => {
    // Logic to fetch deliveries from your database or external API
    // Return an array of delivery objects
  },
};

1. Create an Express.js app and set up the GraphQL endpoint by adding the following code: ```javascript const app = express();

app.use( ‘/graphql’, graphqlHTTP({ schema: schema, rootValue: root, graphiql: true, }) );

app.listen(3000, () => { console.log(‘Server is running on port 3000’); });

6. Save the file and run the following command in your terminal:
```shell
node server.js

Fetching Deliveries

Now that our server is up and running, let’s see how we can fetch deliveries using GraphQL queries. Follow these steps:

1. Open your browser and navigate to http://localhost:3000/graphql.
2. Enter the following query into the GraphQL Playground:

   query {
     deliveries {
    id
    customerName
    destination
    status
     }
   }
   

3. Press the “Play” button to execute the query.
4. You should see the list of deliveries returned as a response.

Conclusion

In this tutorial, we have learned how to set up a delivery tracking system using JavaScript and GraphQL. We have created a server with Express.js and defined a GraphQL schema for deliveries. We have also implemented resolver functions to fetch deliveries from a database or external API. With this foundation, you can now extend the system to include features such as updating delivery status or adding new deliveries.

#JavaScript #GraphQL