Translates a graphql query into a neo4j/graphql query using neo4j/graphql-ogm

runNeo4jGqlQuery.ts

import { GraphQLResolveInfo, FieldNode, SelectionNode, SelectionSetNode, print } from "graphql";
import { ResolverContext } from "./index";

/**
 *
 * Translates a graphql query into a neo4j/graphql query using neo4j/graphql-ogm
 * @see https://github.com/neo4j/graphql/issues/227
 *
 * @param args graphql query args
 * @param info GraphQLResolveInfo
 */
export async function runNeo4jGqlQuery<T>(
  // eslint-disable-next-line @typescript-eslint/no-explicit-any
  args: { where?: any; options?: any },
  context: ResolverContext,
  info: GraphQLResolveInfo,
  custom: { label: string; subField: string } | null = null,
): Promise<Array<T>> {
  const nodeLabel = custom !== null ? custom.label : info.fieldName;
  const type = context.ogm.model(nodeLabel);

  const rootSelectionSet =
    custom !== null
      ? getSubFieldSelectionSet(custom.subField, info.operation.selectionSet)
      : info.operation.selectionSet;

  if (rootSelectionSet !== null) {
    const operationStr = resolveOperationStrWithFragments(info, print(rootSelectionSet));

    const parentHasArgs = Object.keys(args).length > 0;
    const where = parentHasArgs && args.where;
    const options = parentHasArgs && args.options;
    const selectionSet = !parentHasArgs
      ? operationStr.split(nodeLabel.toLowerCase() + "s")[1].slice(0, -1)
      : operationStr.substring(operationStr.indexOf(")") + 1).slice(0, -1);
    return await type.find({ where, selectionSet: custom ? operationStr : selectionSet, options });
  }
  return [];
}

/**
 * Retrieve the GraphQL selectNode that match the given field.
 */
function getSubFieldSelectionSet(field: string, node: SelectionSetNode): SelectionSetNode | null {
  let result: SelectionSetNode | null = null;
  node.selections.forEach((selection: SelectionNode) => {
    if (result === null && Object.prototype.hasOwnProperty.call(selection, "selectionSet")) {
      const castedSeclection = selection as FieldNode;
      if (castedSeclection.name.kind === "Name" && castedSeclection.name.value === field) {
        result = castedSeclection.selectionSet || null;
      } else {
        if (castedSeclection.selectionSet) {
          result = getSubFieldSelectionSet(field, castedSeclection.selectionSet);
        }
      }
    }
  });
  return result;
}

/**
 * Replace fragments by their value for the operation.
 * This operation is recursive because a fragment can use a fragment.
 */
function resolveOperationStrWithFragments(info: GraphQLResolveInfo, operation: string): string {
  let op = operation;
  let shouldContinue = true;
  let index = 0;
  while (shouldContinue && index < 5) {
    op = Object.entries(info.fragments).reduce((operationStr, fragment) => {
      return operationStr.replace(
        `...${fragment[0]}\n`,
        `${print(info.fragments[fragment[0]].selectionSet).substring(1).slice(0, -1)}\n`,
      );
    }, op);
    index++;
    shouldContinue = Object.entries(info.fragments).reduce((acc: boolean, fragment) => {
      if (op.includes(`...${fragment[0]}\n`)) return true;
      else return acc;
    }, false);
  }
  return op;
}