GraphAcademy

Building Neo4j Applications with Node.js

Project Introduction

The Neo4j JavaScript Driver

Interacting with Neo4j

Homework: Project Backlog

Listing People

Optional Lesson

This lesson is optional and will not count towards your achievement. To view the completed code, check out the 14-person-list branch.

If you open click on the People link in the main navigation, you will see a paginated list of actors and directors.

People Search

A list of people can be retrieved by calling the http://localhost:3000/people/ endpoint. The list is populated by the all() method in the PeopleService.

js
src/services/people.service.js
async all(q, sort = 'name', order = 'ASC', limit = 6, skip = 0) {
  // TODO: Get a list of people from the database

  return people.slice(skip, skip + limit)
}

This person lists vary slightly from the movie lists because this features a Search by Name input. When this value is set, an additional q parameter is passed to tx.run(), and if defined, the query adds an additional CONTAINS predicate.

cypher
Find People with CONTAINS predicate
MATCH (p:Person)
WHERE $q IS NULL OR p.name CONTAINS $q
RETURN p { .* } AS person
ORDER BY p.name ASC
SKIP $skip
LIMIT $limit

Using Text Indexes

The STARTS WITH, ENDS WITH and CONTAINS predicates are case-sensitive. If you are looking for a case-insensitive search, you should consider setting up a full-text schema index.

Your Task

  • Modify the all() method to query Neo4j and return a list of people.

  • If the q parameter is defined, add a WHERE clause to check that the name property contains the value provided.

  • Remember to close the session and use the toNativeTypes() function within a map() function on res.records to convert the values to native JavaScript types.

Open src/services/people.service.js →
Click to reveal the completed all() method
js
src/services/people.service.js
async all(q, sort = 'name', order = 'ASC', limit = 6, skip = 0) {
  // Open a new database session
  const session = this.driver.session()

  // Get a list of people from the database
  const res = await session.executeRead(
    tx => tx.run(`
      MATCH (p:Person)
      ${q !== undefined ? 'WHERE p.name CONTAINS $q' : ''}
      RETURN p { .* } AS person
      ORDER BY p.${sort} ${order}
      SKIP $skip
      LIMIT $limit
    `, { q, skip: int(skip), limit: int(limit) })
  )

  // Close the session
  await session.close()

  return res.records.map(row => toNativeTypes(row.get('person')))
}

Testing

To test that this functionality has been correctly implemented, run the following code in a new terminal session:

sh
Running the test
npm run test 14

The test file is located at test/challenges/14-person-list.spec.js.

Are you stuck? Click here for help

If you get stuck, you can see a working solution by checking out the 14-person-list branch by running:

sh
Check out the 14-person-list branch
git checkout 14-person-list

You may have to commit or stash your changes before checking out this branch. You can also click here to expand the Support pane.

Verifying the Test

What is the name of the first person in the database in alphabetical order?

As part of the test suite, the final test will log the name of the first person to appear in the database in name order.

Paste the name of the person the box below without quotes or whitespace and click Check Answer.

  • ✓ 'Snub' Pollard

Hint

You can also find the answer by running the following Cypher statement:

cypher
MATCH (p:Person)
RETURN p.name
ORDER BY p.name ASC LIMIT 1

Copy the answer without any double quotes or whitespace.

Lesson Summary

In this Challenge, you implemented the all() method in the PeopleService to return a paginated list of people from the Neo4j database and implemented a conditional WHERE clause on the Person name property.

In the next Challenge, you will retrieve an individual’s details from the database.