@hammerbot/cypher-query-builder

Cypher Query Builder

A flexible and intuitive query builder for Neo4j and Cypher. Write queries in Javascript just as you would write them in Cypher.

• Easy to use fluent interface
• Support for streaming records using observables
• Full Typescript declarations included in package

let results = await db.matchNode('user', 'User', { active: true })
  .where({ 'user.age': greaterThan(18) })
  .with('user')
  .create([
    cypher.node('user', ''),
    cypher.relation('out', '', 'HasVehicle'),
    cypher.node('vehicle', 'Vehicle', { colour: 'red' })
  ])
  .ret(['user', 'vehicle'])
  .run();

// Results:
// [{
//   user: {
//     identity: 1234,
//     labels: [ 'User' ],
//     properties: { ... },
//   },
//   vehicle: {
//     identity: 4321,
//     labels: [ 'Vehicle' ],
//     properties: { ... },
//   },
// }]

Contents

• Quick start
  • Installation
  • Importing
  • Connecting
  • Querying
  • Processing
• Documentation
• Contributing
• License

Quick start

Installation

npm install --save cypher-query-builder

or

yarn install cypher-query-builder

Importing

CommonJS/Node

const cypher = require('cypher-query-builder');
// cypher.Connection
// cypher.greaterThan
// ....

ES6

import { Connection, greaterThan } from 'cypher-query-builder';

Connecting

const cypher = require('cypher-query-builder');

// Make sure to include the protocol in the hostname
let db = new cypher.Connection('bolt://localhost', {
  username: 'root',
  password: 'password',
});

Cypher query builder uses the official Neo4j Nodejs driver over the bolt protocol in the background so you can pass any values into connection that are accepted by that driver.

Querying

ES6

db.matchNode('projects', 'Project')
  .return('projects')
  .run()
  .then(function (results) {
    // Do something with results
  });

ES2017

const results = await db.matchNode('projects', 'Project')
  .return('projects')
  .run();

run will execute the query and return a promise. The results are in the standardish Neo4j form an array of records:

const results = [
  {
    projects: {
      // Internal Neo4j node id, don't rely on this to stay constant.
      identity: 1,

      // All labels attached to the node
      labels: [ 'Project' ],

      // Actual properties of the node.
      // Note that Neo4j numbers will automatically be converted to
      // Javascript numbers. This may cause issues because Neo4j can
      // store larger numbers than can be represented in Javascript.
      // This behaviour is currently in consideration and may change
      // in the future.
      properties: { name: 'Project 1' },
    },
  },
  // ...
]

You can also use the stream method to download the results as an observable.

const results = db.matchNode('project', 'Project')
  .ret('project')
  .stream();

results.subscribe(row => console.log(row.project.properties.name));

Under the hood, the promises and observables used by this library are constructed by any-promise and any-observable respectively. They default to using the global Promise class and the RxJS observable library, but you can change that by registering another implementation before importing this module.

Processing

To extract the results, you can use ES5 array methods or a library like lodash:

// Get all the project nodes (including their id, labels and properties).
let projects = results.map(row => row.projects);

// Get just the properties of the nodes
let projectProps = results.map(row => row.projects.properties);

Documentation

All the reference documentation can be found here. However, the two most useful pages are probably:

• The Connection class, for details on creating and using a connection.
• The Query class, for details on all the available clauses, and building and running queries.

Contributing

Please feel free to submit any bugs or questions you may have in an issue. I'm very open to discussing suggestions or new ideas so don't hesitate to reach out.

Maintaining the library does take some time out of my schedule so if you'd like to show your appreciation please consider donating. Even the smallest amount is really encouraging.

License

MIT License

Copyright (c) 2018 James Ferguson

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.