Batch put custom resolver

type Todo @model {
  id: ID!
  name: String!
  description: String
}

type Mutation {
  batchCreateTodo(todos: [BatchCreateTodo]): [Todo]
}

input BatchCreateTodo {
  id: ID
  name: String!
  description: String
}

amplify add custom

? How do you want to define this custom resource?
❯ AWS CDK
? Provide a name for your custom resource
❯ MyCustomResolvers

cd amplify/backend/custom/MyCustomResolvers
npm i @aws-cdk/aws-appsync@~1.124.0

import * as cdk from '@aws-cdk/core';
import * as AmplifyHelpers from '@aws-amplify/cli-extensibility-helper';
import * as appsync from '@aws-cdk/aws-appsync';
import { AmplifyDependentResourcesAttributes } from '../../types/amplify-dependent-resources-ref';

export class cdkStack extends cdk.Stack {
  constructor(scope: cdk.Construct, id: string, props?: cdk.StackProps, amplifyResourceProps?: AmplifyHelpers.AmplifyResourceProps) {
    super(scope, id, props);
    /* Do not remove - Amplify CLI automatically injects the current deployment environment in this input parameter */
    new cdk.CfnParameter(this, 'env', {
      type: 'String',
      description: 'Current Amplify CLI env name',
    });
    
    // Access other Amplify Resources 
    const retVal:AmplifyDependentResourcesAttributes = AmplifyHelpers.addResourceDependency(this, 
      amplifyResourceProps.category, 
      amplifyResourceProps.resourceName, 
      [{
        category: "api",
        resourceName: "<YOUR-API-NAME>"
      }]
    );

    const requestVTL = `
      ## [Start] Initialization default values. **
      $util.qr($ctx.stash.put("defaultValues", $util.defaultIfNull($ctx.stash.defaultValues, {})))
      #set( $createdAt = $util.time.nowISO8601() )
      #set($todosArray = [])
      #foreach($item in \${ctx.args.todos})
        $util.qr($item.put("id", $util.defaultIfNullOrBlank($item.id, $util.autoId())))
        $util.qr($item.put("createdAt", $util.defaultIfNull($item.createdAt, $createdAt)))
        $util.qr($item.put("updatedAt", $util.defaultIfNull($item.updatedAt, $createdAt)))
        $util.qr($item.put("__typename", "Todo"))
        $util.qr($todosArray.add($util.dynamodb.toMapValues($item)))
      #end
      ## [End] Initialization default values. **
      $util.toJson( {
        "version": "2018-05-29",
        "operation": "BatchPutItem",
        "tables": {
          "<TYPE-NAME-HERE>-${apiIdRef}-${envRef}": $todosArray
        }
      } )
    `
    const responseVTL = `
      ## [Start] ResponseTemplate. **
      #if( $ctx.error )
        $util.error($ctx.error.message, $ctx.error.type)
      #else
        $util.toJson($ctx.result.data.<TYPE-NAME-HERE>-${apiIdRef}-${envRef})
      #end
      ## [End] ResponseTemplate. **
    `;


    const resolver = new appsync.CfnResolver(this, "custom-resolver", {
      // apiId: retVal.api.new.GraphQLAPIIdOutput,
      // https://github.com/aws-amplify/amplify-cli/issues/9391#event-5843293887
      // If you use Amplify you can access the parameter via Ref since it's a CDK parameter passed from the root stack.
      // Previously the ApiId is the variable Name which is wrong , it should be variable value as below
      apiId: cdk.Fn.ref(retVal.api.replaceWithAPIName.GraphQLAPIIdOutput),
      fieldName: "querySomething", 
      typeName: "Query", // Query | Mutation | Subscription
      requestMappingTemplate: requestVTL,
      responseMappingTemplate: responseVTL,
      dataSourceName: "TodoTable" // DataSource name
    })
  }
}