@acastellon/neo4j

Neo4j persistence interface (using official neo4j-driver v5+).

Install

npm install @acastellon/neo4j

Config example

See config.neo4j.template.js (uses bolt:// by default).

module.exports = {
  NEO4J_URL: 'bolt://127.0.0.1:11002',
  NEO4J_USER: 'neo4j',
  NEO4J_PASSWORD: 'neo4j2019',
  TRACES: true
};

Usage

const config = require('./config.neo4j.template.js');
const neo = require('@acastellon/neo4j')(config);

neo.execute('MATCH (n) RETURN n LIMIT 1', {}).then(console.log);

API

getConnection(): Driver

Returns a new driver connection (for advanced reuse).

Example (with minimal setup):

const config = require('./config.neo4j.template.js');
const neo = require('@acastellon/neo4j')(config);

const conn = neo.getConnection();
const session = conn.session();
// use session, then close when done
session.close();
conn.close();

execute(cypher, parameters, [options]): Promise

Executes and returns transformed results (neo4j ints -> JS numbers/strings, nested objects recursed).

• options: { conn, session, close: bool }

Example (with minimal setup):

const config = require('./config.neo4j.template.js');
const neo = require('@acastellon/neo4j')(config);

const cypher = 'MATCH (s:Substance)-[r:IS_A]-(c) RETURN s,r,c LIMIT 3';

neo.execute(cypher, {})
  .then(results => console.log(results))
  .catch(err => console.error(err));

executeAsPromise(cypher, parameters, [options]): Promise

Similar, returns the raw records array after transform.

Example (with minimal setup):

const config = require('./config.neo4j.template.js');
const neo = require('@acastellon/neo4j')(config);

const cypher = 'MATCH (n) RETURN n LIMIT 1';

neo.executeAsPromise(cypher, {})
  .then(records => console.log(records))
  .catch(err => console.error(err));

executeAsStream(cypher, parameters, [options]): Readable

For large result sets.

Example (with minimal setup):

const config = require('./config.neo4j.template.js');
const neo = require('@acastellon/neo4j')(config);

const { Writable } = require('stream');

const cypher = 'MATCH (n) RETURN n LIMIT 100';

const outStream = new Writable({
  write(chunk, encoding, callback) {
    console.log(JSON.parse(chunk.toString()));
    callback();
  }
});

neo.executeAsStream(cypher, {}, { close: true })
  .pipe(outStream);

executeBatch(queries: Array<{cypher, parameters}>, [options]): Promise

Transaction batch. Note: current impl resolves after commit subscribe.

Example (with minimal setup):

const config = require('./config.neo4j.template.js');
const neo = require('@acastellon/neo4j')(config);

const queries = [
  { cypher: 'MERGE (s:Person {name: $name}) RETURN s', parameters: { name: 'Alice_1' } },
  { cypher: 'MATCH (s:Person {name: $name}) DELETE s', parameters: { name: 'Alice_1' } }
];

neo.executeBatch(queries)
  .then(success => console.log('Batch success:', success))
  .catch(err => console.error(err));

License

MIT