@graphile-contrib/pg-order-by-related

This Graphile Engine plugin adds additional enum values to the orderBy argument on connections, allowing you to order by columns in related tables.

Requires postgraphile@^4.3.1 or graphile-build-pg@^4.3.1

Example:

{
  # additional enum values exposed here 👇
  allPosts(orderBy: PERSON_BY_AUTHOR_ID__CREATED_AT_ASC) {
    nodes {
      headline
      personByAuthorId {
        id
        name
        about
      }
    }
  }
}

One-to-one and many-to-one relations are supported. For one-to-many relations, __COUNT_ASC/__COUNT_DESC enums allow ordering by the number of related records.

Usage

Append this plugin and the additional orderBy options will be added to your schema.

CLI

yarn add postgraphile
yarn add @graphile-contrib/pg-order-by-related
npx postgraphile --append-plugins @graphile-contrib/pg-order-by-related

Library

const express = require("express");
const { postgraphile } = require("postgraphile");
const PgOrderByRelatedPlugin = require("@graphile-contrib/pg-order-by-related");

const app = express();

app.use(
  postgraphile(process.env.DATABASE_URL, "app_public", {
    appendPlugins: [PgOrderByRelatedPlugin],
    graphiql: true,           
  })
);

app.listen(5000);

Inflection

To avoid naming conflicts, this plugin uses a <TABLE>_BY_<KEY> naming convention (e.g. USER_BY_AUTHOR_ID__CREATED_AT_ASC), similar to how related fields are named by default in PostGraphile v4.

You can override this by adding an inflector plugin. For example, the following plugin shortens the names by dropping the <TABLE>_BY portion (producing e.g. AUTHOR_ID__CREATED_AT_ASC):

const { makeAddInflectorsPlugin } = require("graphile-utils");

module.exports = makeAddInflectorsPlugin(
  {
    orderByRelatedColumnEnum(attr, ascending, foreignTable, keyAttributes) {
      return `${this.constantCase(
        keyAttributes.map(keyAttr => this._columnName(keyAttr)).join("-and-")
      )}__${this.orderByColumnEnum(attr, ascending)}`;
    },
  },
  true // Passing true here allows the plugin to overwrite existing inflectors.
);

See the makeAddInflectorsPlugin documentation for more information.

Options

When using PostGraphile as a library, the following options can be specified via graphileBuildOptions.

orderByRelatedColumnAggregates

Adds additional enum values for column aggregates (currently min and max) for one-to-many relationships.

Example:

postgraphile(pgConfig, schema, {
  graphileBuildOptions: {
    orderByRelatedColumnAggregates: true,
  },
})

{
  allPersons(orderBy: POSTS_BY_AUTHOR_ID__MAX_CREATED_AT_ASC, first: 10) {
    nodes {
      id
      name
    }
  }
}

Development

To establish a test environment, create an empty PostgreSQL database and set a TEST_DATABASE_URL environment variable with your database connection string.

createdb graphile_test
export TEST_DATABASE_URL=postgres://localhost:5432/graphile_test
yarn
yarn test