GraphQL 选择集解析

Question

I have this GraphQL Selection Set inside my AppSync Lambda Resolver:

{
  recommendationId
  items {
    id
    name
  }
}

I need the selection set inside items , which will be heavily nested.

How can I get this output?

{
  id
  name
}

Context(replaced business object with Object ):

schema.graphql

type Object {
 id: ID!
 name: String!
}

type Query {
 getObjectsById(objectsById: ObjectsByID!): [Object] 
 listRecommendedObjects(personId: ID!): RecommendedObjects
}

input ObjectsByID {
  ids: [ID!]!
}

type RecommendedObjects {
  items: [Object]
  recommendationId: String
}

Inside resolver:

const buildQuery = (selectionSetGraphQL) =>
  `query MyQuery($objectsById: ObjectsByID!) {
    getObjectsById(objectsById: $objectsById) ${selectionSetGraphQL}
  }`

Goal:

Call listRecommendedObjects which will invoke custom lambda that will talk to AWS Personalize to get item IDs. Then, i want to use the selection set of Object to call getObjectsById within that Lambda to get the data of Item IDs from Personalize

Answer 1

I got a sensible solution using graphql-js .

I use parse , then select what I need, then convert it back to a string with print

const { parse, print } = require("graphql/language")

const document = parse('{ id items {id name} }')

const subSet = document
  .definitions[0]
  .selectionSet
  .selections
  .find(elem => elem.name.value == 'items')

print(subSet) // => `items {id name}`