graphql-compose-connection

This is a plugin for graphql-compose family, which adds to the TypeComposer connection resolver.

Live demo: https://graphql-compose.herokuapp.com/

This package completely follows to Relay Cursor Connections Specification (https://facebook.github.io/relay/graphql/connections.htm).

Besides standard connection arguments first, last, before and after, also added significant arguments:

• filter arg - for filtering records
• sort arg - for sorting records. Build in mechanism allows sort by any unique indexes (not only by id). Also supported compound sorting (by several fields).

CHANGELOG

Installation

npm install graphql graphql-compose graphql-compose-connection --save

Modules graphql and graphql-compose are in peerDependencies, so should be installed explicitly in your app. They should not installed as submodules, cause internally checks the classes instances.

Example

import composeWithConnection from 'graphql-compose-connection';
import userTypeComposer from './user.js';

composeWithConnection(userTypeComposer, {
  findResolverName: 'findMany',
  countResolverName: 'count',
  sort: {
    // Sorting key, visible for users in GraphQL Schema
    _ID_ASC: {
      // Sorting value for ORM/Driver
      value: { _id: 1 },

      // Field names in record, which data will be packed in `cursor`
      //   edges {
      //     cursor   <- base64(cursorData), for this example `cursorData` = { _id: 334ae453 }
      //     node     <- record from DB
      //   }
      // By this fields MUST be created UNIQUE index in database!
      cursorFields: ['_id'],

      // If for connection query provided `before` argument with above `cursor`.
      // We should construct (`rawQuery`) which will be point to dataset before cursor.
      // Unpacked data from `cursor` will be available in (`cursorData`) argument.
      // PS. All other filter options provided via GraphQL query will be added automatically.
      // ----- [record] -----   sorted dataset, according to above option with `value` name
      // ^^^^^                 `rawQuery` should filter this set    
      beforeCursorQuery: (rawQuery, cursorData, resolveParams) => {
        if (!rawQuery._id) rawQuery._id = {};
        rawQuery._id.$lt = cursorData._id;
      },

      // Constructing `rawQuery` for connection `after` argument.
      // ----- [record] -----   sorted dataset
      //                ^^^^^  `rawQuery` should filter this set    
      afterCursorQuery: (rawQuery, cursorData, resolveParams) => {
        if (!rawQuery._id) rawQuery._id = {};
        rawQuery._id.$gt = cursorData._id;
      },
    },

    _ID_DESC: {
      value: { _id: -1 },
      cursorFields: ['_id'],
      beforeCursorQuery: (rawQuery, cursorData, resolveParams) => {
        if (!rawQuery._id) rawQuery._id = {};
        rawQuery._id.$gt = cursorData._id;
      },
      afterCursorQuery: (rawQuery, cursorData, resolveParams) => {
        if (!rawQuery._id) rawQuery._id = {};
        rawQuery._id.$lt = cursorData._id;
      },
    },

    // More complex sorting parameter with 2 fields
    AGE_ID_ASC: {
      value: { age: 1, _id: -1 },
      // By these fields MUST be created COMPOUND UNIQUE index in database!
      cursorFields: ['age', '_id'],
      beforeCursorQuery: (rawQuery, cursorData, resolveParams) => {
        if (!rawQuery.age) rawQuery.age = {};
        if (!rawQuery._id) rawQuery._id = {};
        rawQuery.age.$lt = cursorData.age;
        rawQuery._id.$gt = cursorData._id;
      },
      afterCursorQuery: (rawQuery, cursorData, resolveParams) => {
        if (!rawQuery.age) rawQuery.age = {};
        if (!rawQuery._id) rawQuery._id = {};
        rawQuery.age.$gt = cursorData.age;
        rawQuery._id.$lt = cursorData._id;
      },
    }
  },
});

Requirements

Types should have following resolvers:

• count - for counting records
• findMany - for filtering records. Also required that this resolver supports search with operators (lt, gt), which used in directionFilter option. Resolver findMany should have filter argument, which will be copied to connection. Also should have limit and skip args.

Used in plugins

graphql-compose-mongoose - converts mongoose models to graphql types

License

MIT