GraphAcademy

Building Neo4j Applications with TypeScript

Neo4j & TypeScript

Creating a Driver Instance

In this challenge you will:

  1. Connect to a Neo4j database

  2. Open a new session

  3. Run a Cypher statement to find the director of Toy Story.

You must set up a development environment to run the code.

Get started

The repository, neo4j-graphacademy/app-typescript, has been created for this course. It contains any starter code and resources you need.

You can use a GitHub codespace as an online IDE and workspace for this course. It will automatically clone the course repository and set up your environment.

GitHub Codespaces

You will need to login with a GitHub account. The GitHub Codespaces free monthly usage will cover the duration of this course.

Open in GitHub Codespace

Develop on your local machine

You will need NodeJS installed and the ability to install packages using npm.

Clone the github.com/neo4j-graphacademy/app-typescript repository:

bash
git clone https://github.com/neo4j-graphacademy/app-typescript

Install the required packages using npm:

bash
npm install
npm i typescript ts-node

You do not need to create a Neo4j database as you will use the provided sandbox instance.

Setup the environment

Create a copy of the .env.example file and name it .env. Fill in the required values.

Create a .env file
NEO4J_URI="bolt://..."
NEO4J_USERNAME="neo4j"
NEO4J_PASSWORD="..."

Update the Neo4j sandbox connection details:

NEO4J_URI

bolt://{sandbox-ip}:{sandbox-boltPort}

NEO4J_USERNAME

{sandbox-username}

NEO4J_PASSWORD

{sandbox-password}

Steps

Open the src/challenges/create-driver/challenge.ts file that contains the starter code.

typescript
src/challenges/create-driver/challenge.ts
import dotenv from 'dotenv'; 
dotenv.config({ path: '.env' });

// Import the driver
import neo4j, { Integer, Node, Relationship } from 'neo4j-driver'
import { getNeo4jCredentials } from '../utils'

// Neo4j Credentials
const {
  NEO4J_URI,
  NEO4J_USERNAME,
  NEO4J_PASSWORD
} = getNeo4jCredentials()

async function main() {
  // TODO: Create a Driver Instance using neo4j.driver()

  // TODO: Open a new Session using driver.session()

  try {
    const cypher = `
      MATCH (p:Person)-[:DIRECTED]->(:Movie {title: $title})
      RETURN p.name AS Director
    `
    const params = { title: 'Toy Story' }

    // TODO: Run the Cypher statement using session.run()

    // TODO: Log the Director value of the first record

  }
  finally {
    // TODO: Close the session
  }
}

main()

  1. Use the neo4j object to create a new instance of the Driver with the credentials provided:

    • NEO4J_URI is the connection string

    • NEO4J_USERNAME and NEO4J_PASSWORD should be used to create the authentication token.

    typescript
      const driver = neo4j.driver(
    NEO4J_URI,
    neo4j.auth.basic(NEO4J_USERNAME, NEO4J_PASSWORD)
  )

  2. Open a new session:

    typescript
      const session = driver.session()

  3. Use the session to run the Cypher query to find the director of Toy Story:

    typescript
        const cypher = `
      MATCH (p:Person)-[:DIRECTED]->(:Movie {title: $title})
      RETURN p.name AS Director
    `
    const params = { title: 'Toy Story' }

    // Run the Cypher statement using session.run()
    const res = await session.run(cypher, params)

  4. Log the result to the console:

    typescript
        console.log(res.records[0].get('Director'))

  5. Finally, close the session:

    await session.close()
View the complete code
ts
import dotenv from 'dotenv'; 
dotenv.config({ path: '.env' });

// Import the driver
import neo4j, { Integer, Node, Relationship } from 'neo4j-driver'
import { getNeo4jCredentials } from '../utils'

// Neo4j Credentials
const {
  NEO4J_URI,
  NEO4J_USERNAME,
  NEO4J_PASSWORD
} = getNeo4jCredentials()

async function main() {
  // Create a Driver Instance using neo4j.driver()
  const driver = neo4j.driver(
    NEO4J_URI,
    neo4j.auth.basic(NEO4J_USERNAME, NEO4J_PASSWORD)
  )

  // Open a new Session using driver.session()
  const session = driver.session()

  try {
    const cypher = `
      MATCH (p:Person)-[:DIRECTED]->(:Movie {title: $title})
      RETURN p.name AS Director
    `
    const params = { title: 'Toy Story' }

    // Run the Cypher statement using session.run()
    const res = await session.run(cypher, params)

    // Log the Director value of the first record
    console.log(res.records[0].get('Director'))
  }
  finally {
    // Close the session
    await session.close()
  }
}

main()

Run the Challenge

Run the file using ts-node to view the result:

sh
ts-node src/challenges/create-driver/challenge.ts

Once you have the result, copy and paste it into the text box below and click Check Answer.

Your Answer

Who directed Toy Story?

Take the Director value output from the statement above and paste it into the box below.

  • ✓ John Lasseter

Hint

You need to call the neo4j.driver() object to create a Driver instance using the NEO4J_URI, NEO4J_USERNAME and NEO4J_PASSWORD variables, then open a new session, execute the Cypher statement and log the Director value of the first record.

Your console.log() statement should look similar to the code block below:

ts
console.log(res.records[0].get('Director'))

Copy the answer without any quotes or whitespace.

Solution

John Lasseter directed Toy Story.

Compare your code with the solution here

ts
import dotenv from 'dotenv'; 
dotenv.config({ path: '.env' });

// Import the driver
import neo4j, { Integer, Node, Relationship } from 'neo4j-driver'
import { getNeo4jCredentials } from '../utils'

// Neo4j Credentials
const {
  NEO4J_URI,
  NEO4J_USERNAME,
  NEO4J_PASSWORD
} = getNeo4jCredentials()

async function main() {
  // Create a Driver Instance using neo4j.driver()
  const driver = neo4j.driver(
    NEO4J_URI,
    neo4j.auth.basic(NEO4J_USERNAME, NEO4J_PASSWORD)
  )

  // Open a new Session using driver.session()
  const session = driver.session()

  try {
    const cypher = `
      MATCH (p:Person)-[:DIRECTED]->(:Movie {title: $title})
      RETURN p.name AS Director
    `
    const params = { title: 'Toy Story' }

    // Run the Cypher statement using session.run()
    const res = await session.run(cypher, params)

    // Log the Director value of the first record
    console.log(res.records[0].get('Director'))
  }
  finally {
    // Close the session
    await session.close()
  }
}

main()

Click here to view the solution.

Lesson Summary

In this challenge, you used your knowledge to create a driver instance and run a Cypher statement.

In the next lesson, you will learn about the different transaction functions and when to use them.