CypherEngine

Introduction

Cypher Engine is a fully tested Cypher query engine which generates queries in a functional, easy to read, and simple way. It is designed for NodeJS and written in TypeScript.

Premise

This documentation does not explain how Cypher works nor does it try to be a tutorial for Cypher. When using this library it is recommended that you have a good understanding of the Cypher language. Please see the Cyper Documentation for more information.

Usage

npm i cypher-engine

Index

• Create
• Delete
• Match
• Set
• Merge
• Extra

Create

Creating a node in Cypher is the fundamental way to build data in the graph.

const engine = new CypherEngine();

const create = engine
    .create()
    .node(['Person'], 'jeff', new Property('name', `'Jeff'`))
    .toString();

// CREATE (jeff:Person {name: 'Jeff'})

Match

const engine = new CypherEngine();
    const result = engine
      .match()
      .node(['User'], 'u')
      .relates(RelationshipDirection.undirected)
      .node([], 'company')
      .returns('*')
      .toString();

// MATCH (u:User)--(company) RETURN *

Delete

const engine = new CypherEngine();
const result = engine
      .match()
      .node(['User'], 'n0', new Property('email', `'test@test.com'`))
      .relates(RelationshipDirection.left, ['works_for'], undefined, undefined, new Property('years', 5))
      .node(['Company'], 'n1', new Property('name', `'test'`))
      .delete('n0', 'n1')
      .returns()
      .toString();

/* MATCH (n0:User{email:'test@test.com'})<-[:works_for{years:5}]-(n1:Company{name:'test'}
DELETE n0,n1
RETURN *

Set

const engine = new CypherEngine();
const result = engine
      .match()
      .node(['Person'], 'n0', new Property('identifier', '$identifier'))
      .set(new SetProperty('n0', new Property('name', '$name')), new SetProperty('n0', new Property('birthday', '$birthday'))).cypher;

/*`MATCH (n0:Person{identifier:$identifier})
SET n0.name = $name, n0.birthday = $birthday`);
*/

Merge

const engine = new CypherEngine();
const result = engine
      .merge()
      .node(['Person'], 'n0', new Property('name', `'Keanu Reeves'`))
      .onCreate()
      .set(new SetProperty('n0', new Property('created', 123)))
      .onMatch()
      .set()
      .variable('n0', 'modified')
      .equals()
      .value(123)
      .returns()
      .toString();

/* MERGE (n0:Person{name:'Keanu Reeves'})
ON CREATE SET n0.created = 123
ON MATCH SET
n0.modified = 123 RETURN *
*/

Extra

For more complex queries, additonal operators etc... please see the extensive tests in test/CypherEngine.spec.ts