Neo4j-graphql-js custom resolver with custom cypher

pratikmakune3 · July 2, 2021, 12:13pm

Hey community,

I've used GraphQL Architect to generate boilerplate. It has a lean schema.graphql file.
I have a use case to create mutation, I have 3 entities - Product, Material, Functionality. I want to create those as an atomic transaction, I came across a post of @lyonwj, suggesting to run custom cypher either by @cypher directive inside schema or by writing a custom resolver.

My usecase needs writing a custom resolver, as I have to generate slightly different cyphers based on some input args, cypher for this usecase looks a little complex, how can I write the custom cypher query inside a custom resolver, provided I know how to write a custom resolver, I'm not sure how am I supposed to write a custom cypher inside it.

Thanks in advance

michael.hunger · July 2, 2021, 10:32pm

Did you see this video?

and the docs here

github.com

neo4j-graphql/neo4j-graphql-js/blob/dev/docs/graphql-custom-logic.md#implementing-custom-resolvers

# Adding Custom Logic To Our GraphQL API

Adding custom logic to our GraphQL API is necessary any time our application requires logic beyond simple CRUD operations (which are auto-generated by `makeAugmentedSchema`).

There are two options for adding custom logic to your API using neo4j-graphql.js:

1. Using the `@cypher` GraphQL schema directive to express your custom logic using Cypher, or
2. By implementing custom resolvers and attaching them to the GraphQL schema

## The `@cypher` GraphQL Schema Directive

We expose Cypher through GraphQL via the `@cypher` directive. Annotate a field in your schema with the `@cypher` directive to map the results of that query to the annotated GraphQL field. The `@cypher` directive takes a single argument `statement` which is a Cypher statement. Parameters are passed into this query at runtime, including `this` which is the currently resolved node as well as any field-level arguments defined in the GraphQL type definition.

> The `@cypher` directive feature used in the Query API requires the use of the APOC standard library plugin. Be sure you've followed the steps to install APOC in the Project Setup section of this chapter.

### Computed Scalar Fields

We can use the `@cypher` directive to define a custom scalar field, defining a computed field in our schema. Here we add an `averageStars` field to the `Business` type which calculates the average stars of all reviews for the business using the `this` variable.

```graphql

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Neo4j-graphql-js custom resolver with custom cypher

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