https://github.com/geekeast/type-graphql-playground

Build a graphql server with type-graphql
https://github.com/geekeast/type-graphql-playground

aggregation class-transformer class-validator dataloader mongoose type-graphql typedi

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Build a graphql server with type-graphql

• Host: GitHub
• URL: https://github.com/geekeast/type-graphql-playground
• Owner: GeekEast
• Created: 2022-01-22T01:40:33.000Z (almost 3 years ago)
• Default Branch: main
• Last Pushed: 2022-03-04T20:47:47.000Z (over 2 years ago)
• Last Synced: 2023-03-07T21:04:05.024Z (over 1 year ago)
• Topics: aggregation, class-transformer, class-validator, dataloader, mongoose, type-graphql, typedi
• Language: TypeScript
• Homepage:
• Size: 1.35 MB
• Stars: 0
• Watchers: 2
• Forks: 0
• Open Issues: 1
• Metadata Files:
  • Readme: README.md

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README

        


# Type-graphql Playground

  - [Kick off](#kick-off)

  - [Graphql example](#graphql-example)

  - [Regenerate Data](#regenerate-data)

  - [Statistics](#statistics)

  - [Next Phase](#next-phase)

## Kick off

```sh

# install dependency

yarn install

# compose docker

yarn project up

# start graphql server

yarn start

```

## Graphql example

- query http://localhost:12305/graphql

```graphql

query GetGroup($getGroupFilter: GetGroupDto!) {

  GetGroup(filter: $getGroupFilter) {

    _id

    name

    userCount

  }

}

# query with datalodare loadMany() without aggregation help

query GetGroups($getGroupsFilter: GetGroupsDto!) {

  GetGroups(filter: $getGroupsFilter) {

    _id

    name

    userCount

    users {

      _id

      email

      firstName

      lastName

    }

  }

}

# query with dataloader load() method with optmized mongo aggregation query

query GetGroupsViaSingleMongoQuery(

  $getGroupsFilterViaSingleMongoQuery: GetGroupsDto!

) {

  GetGroups(filter: $getGroupsFilterViaSingleMongoQuery) {

    _id

    name

    userCount

    users2 {

      _id

      email

      firstName

      lastName

    }

  }

}

```

- variables: ids is stored in generated `groupIds.json` in project root directory

```json

{

  "getGroupFilter": {

    "_id": "61eabfc67d720e6372867487"

  },

  "getGroupsFilter": {

    "_ids": [

      "61eabfc67d720e6372867487"

    ]

  },

  "getGroupsFilterViaSingleMongoQuery": {

    "_ids": [

      "61eabfc67d720e6372867487"

    ]

  }

}

```

## Regenerate Data

```sh

# generate the seed scripts

yarn project generateSeedScripts

# seed data to mongodb

yarn project seed

# create indices

yarn project index

```

## Statistics

- for query `2000` **groups** with **users**  as sub-document in graphql

- dataloader has two main functionalities here: **batch** requests (deduplicate) and **cache** request (memory)

- 

| Data Loader method  | Aggregation Query | Plain Query |  Time Consumed  | use case                            |

| :-----------------: | :---------------: | :---------: | :-------------: | ----------------------------------- |

|   `load(groupId)`   |        ✅         |             |  `600-1000ms`   | huge amount of fanned out promises  |

| `loadMany(userIds)` |                   |     ✅      | `30000-60000ms` | small amount of fanned out promises |

## Take away

- Graphql **Flexibility**: Favor `field resolver` to assemble **exterior** fields over assembling in `service` layer.

- Delegate **cumbersome** assembling logic from `field resolver` to mongodb `aggregate pipeline`.

## Next Phase

- How to do performant sorting in graphql layer since field resolver happens after data get fetched from database?