Cannot install 'neo4j-driver/lib/graph-types'

Neo4j Graph Platform Server
1

I'm using Server 4.3.2 and developing using JavaScript on an Ubuntu 20.04 machine.

After a system crash, I restarted but the my application server crashed at startup, with the error Cannot find module 'neo4j-driver/lib/graph-types'

I look all around the machine, but there is no file with such a name.

Then I look on the internet and I find the 'official drive for Javascript' on the npm site.

They suggest to npm install neo4j-driver and I have done it but the files is still missing.

I remember that it was part of a neo4j example on how to use neo4j with javascript.

Has anyone some idea on how to retrieve that file?

Thank you

2

Hi @p.dipietro ,

I think graph-types was a specific file in an older distribution of the driver. For the current driver the imports look different. The top-level neo4j object should encapsulate everything you need.

[Edit/update] OK, so there is still a graph-types in the core package, which is an internal module not meant for public use. neo4j-javascript-driver/graph-types.ts at 4.3 · neo4j/neo4j-javascript-driver · GitHub

Which types are you using? And, are you writing client-side javascript or nodejs?

Best,
ABK

3

As a minimal example, this jest test imports neo4j then confirms that neo4j.types is a sub-object...

const neo4j = require('neo4j-driver')

describe("neo4j-driver types", () => {
  it("are a sub-object", () => {
    const neo4jTypes = neo4j.types;
    expect(neo4jTypes).toBeDefined();
  })
})

This has inspired a github repo where I'll accumulate minimal viable code examples: GitHub - akollegger/neo4j-js-examples: Collection of minimal viable code snippets which demonstrate some aspect of the neo4j-js drivers.

4

Hi @abk, I'm writing node.

In the article.js file (which cames from a neo4j example) there is an const neo4j = require('../neo4j).

Into that neo4j.js file there is a const neo4j=require('neo4j-driver').

Now, I have a neo4j-type-handler.js into the middleware folder. The initial lines are

const {
    isDuration,
    isLocalTime,
    isTime,
    isDate,
    isDateTime,
    isLocalDateTime,
    isInt,
    isPoint,
    types,
 } = require('neo4j-driver');
----> const { isNode, isRelationship } = require('neo4j-driver/lib/graph-types')
const { Result } = types

The line marked with an arrow is the offending one: the system crashes.

I deleted that file two days ago, because it was of an old version, without imagining the subsequent mess!

So, the question is how can I patch the program?

If I add const { isNode, isRelationship } = require('neo4j-driver);
when I call the page from the browser it returns the following error:

TypeError: isNode is not a function
   at toNative (/node/app/src/middleware/neo4j-type-handler.js:28:15)
   at /node/app/src/middleware/neo4j-type-handler.js:24:40

and in neo4j-type-handler

...
28    else if ( isNode(value) ) return toNative({
...

I'm really without an idea on how to solve the problem.

Any suggestion will be appreciated.
Thank you
Paolo

5

OK, isNode does not seem to be public. It's only available in the neo4j-driver-core module, which is described as being for internal use (not end-user). Nevertheless, that's what you'll need to use to get what you need.

I've updated GitHub - akollegger/neo4j-js-examples: Collection of minimal viable code snippets which demonstrate some aspect of the neo4j-js drivers. to use that module. Here's the relevant code snippet for nodejs:

// This is only available from the non-public api...
const {isNode, Node} = require('neo4j-driver-core');

describe("neo4j-driver types", () => {
  describe("Node", () => {
    it("can be constructed", () => {
      const identity = 0;
      const labels = ["A"];
      const properties = {
        k: "value"
      }
      const n = new Node(identity, labels, properties)
      expect(n.identity).toBe(identity);
      expect(n.labels).toEqual(expect.arrayContaining(labels));
      expect(n.properties).toMatchObject(properties);
    })
  })
  it("isNode", () => {
    const identity = 0;
    const labels = ["A"];
    const properties = {
      k: "value"
    }
    const n = new Node(identity, labels, properties)
    expect(isNode(n)).toBeTruthy();
  })
})

Hope that helps.

Best,
ABK

References

6

Thank you!

IsRelationship is also needed!

My package.json file contains "neo4j-driver": "^4.3.2",

Following the instruction, I run npm install neo4j-driver into my project directory, but I'm not sure that it is the right way.

Which is the easiest way to download and install this new modules?

Paolo

7

The new module can be added to your project by doing this:

npm install neo4j-driver-core

It'll be important to pay attention to the version in package.json, that both neo4j-driver and
neo4j-driver-core are at the same version.

I've updated the neo4j-js-examples project with usage of isRelationship() and new Relationship().

Best,
ABK