Appsync dynamodb JS

01-schema.graphqls

type ItemsResponse {
	listid: ID!
	items: [ListItem]
}

type ListItem {
	listid: ID!
	ts_uuid: ID!
	title: String!
	done: Boolean!
}

type Mutation {
	putItem(listid: ID!, title: String!): ListItem
}

type Query {
	items(listid: ID!): ItemsResponse
}

schema {
	query: Query
	mutation: Mutation
}

02-items-resolver.js

import { util } from "@aws-appsync/utils";

/**
 * Queries a DynamoDB table for items based on the `id` and that contain the `tag`
 * @param {import('@aws-appsync/utils').Context<{listid: string}>} ctx the context
 * @returns {import('@aws-appsync/utils').DynamoDBQueryRequest} the request
 */
export function request(ctx) {
  const query = JSON.parse(
    util.transform.toDynamoDBConditionExpression({
      listid: { eq: ctx.args.listid },
    }),
  );
  return { operation: "Query", query };
}

/**
 * Returns the query items
 * @param {import('@aws-appsync/utils').Context} ctx the context
 * @returns {{listid, items: {listid, ts_uuid, title, done}}} a flat list of result items
 */
export function response(ctx) {
  if (ctx.error) {
    util.error(ctx.error.message, ctx.error.type);
  }
  return {
      listid: ctx.args.listid,
      items: ctx.result.items.map(item => ({
          listid: item['listid'],
          ts_uuid: item['ts-uuid'],
          title: item['title'],
          done: item['done'],
      }))
  };
}

03-putItem-resolver.js

import { util } from "@aws-appsync/utils";

/**
 * Puts an item into the DynamoDB table using an auto-generated ID.
 * @param {import('@aws-appsync/utils').Context<{listid, title}>} ctx the context
 * @returns {import('@aws-appsync/utils').DynamoDBPutItemRequest} the request
 */
export function request(ctx) {
  return {
    operation: "PutItem",
    key: util.dynamodb.toMapValues({ listid: ctx.args.listid, 'ts-uuid': '' + util.time.nowEpochMilliSeconds() + '-' + util.autoId() }), // have a predictable yet unique range key
    attributeValues: util.dynamodb.toMapValues({
        title: ctx.args.title,
        done: false,
    }),
  };
}

/**
 * Returns the item or throws an error if the operation failed
 * @param {import('@aws-appsync/utils').Context} ctx the context
 * @returns {{listid, ts_uuid, title, done}} the inserted item
 */
export function response(ctx) {
  if (ctx.error) {
    util.error(ctx.error.message, ctx.error.type);
  }
  return {
      listid: ctx.result['listid'],
      ts_uuid: ctx.result['ts-uuid'],
      title: ctx.result['title'],
      done: ctx.result['done'],
  };
}

04-queries.graphql

query {
  items(listid:"abc-123") {
    listid,
    items {
      ts_uuid,
      title,
      done
    }
  }
}

mutation {
  putItem(listid:"abc-123", title:"Create a gist") {
    listid,
    ts_uuid,
    title,
    done
  }
}

05-testdata.csv