@graphile-contrib/pg-simplify-inflector

@graphile-contrib/pg-simplify-inflector

This plugin simplifies field names in the PostGraphile schema; e.g. allUsers becomes simply users, User.postsByAuthorId becomes simply User.posts, and Post.userByAuthorId becomes simply Post.author.

Adding this plugin to your schema is almost certainly a breaking change, so do it before you ship anything! This is the primary reason this isn't enabled by default in PostGraphile.

This plugin is recommended for all PostGraphile users.

Customising

This plugin is implemented as a single JS file that does not need to be compiled at all - you can simply copy it into your project and customise it as you see fit.

Alternatively, you can write your own inflection plugin.

Changes:

Given these tables:

create table companies (
  id serial primary key,
  name text not null
);
create table beverages (
  id serial primary key,
  company_id int not null references companies,
  distributor_id int references companies,
  name text not null
);

• Query.allCompanies 👉 Query.companies (disable via pgSimplifyAllRows = false)
• Query.allBeverages 👉 Query.beverages
• Beverage.companyByCompanyId 👉 Beverage.company
• Beverage.companyByDistributorId 👉 Beverage.distributor
• Company.beveragesByCompanyId 👉 Company.beverages (because the company_id column follows the [table_name]_id naming convention)
• All update mutations now accept patch instead of companyPatch / beveragePatch (disable via pgSimplifyPatch = false)
• If you are using pgSimpleCollections = "only" then you can set pgOmitListSuffix = true to omit the List suffix
• Fields where the singular and plural are the same and a distinct plural is required are force-pluralised ("fishes") to avoid conflicts (e.g. singularize("fish") === pluralize("fish")).

Note: Company.beveragesByDistributorId will remain, because distributor_id does not follow the [table_name]_id naming convention, but you could rename this yourself with a smart comment:

comment on constraint "beverages_distributor_id_fkey" on "beverages" is
  E'@foreignFieldName distributedBeverages';

or with a custom inflector:

module.exports = makeAddInflectorsPlugin(
  {
    getOppositeBaseName(baseName) {
      return (
        {
          // These are the default opposites
          parent: "child",
          child: "parent",
          author: "authored",
          editor: "edited",
          reviewer: "reviewed",

          // 👇 Add/customise this line:
          distributor: "distributed",
        }[baseName] || null
      );
    },
  },
  true
);

Installation:

yarn add @graphile-contrib/pg-simplify-inflector

or

npm install --save @graphile-contrib/pg-simplify-inflector

Usage:

CLI:

postgraphile --append-plugins @graphile-contrib/pg-simplify-inflector

Library:

const PgSimplifyInflectorPlugin = require("@graphile-contrib/pg-simplify-inflector");

// ...

app.use(
  postgraphile(process.env.AUTH_DATABASE_URL, "app_public", {
    appendPlugins: [PgSimplifyInflectorPlugin],

    // Optional customisation
    graphileBuildOptions: {
      /*
       * Uncomment if you are using `simpleCollections: 'only'` and you never
       * want relay connections
       */
      //pgOmitListSuffix: true,
      /*
       * Uncomment if you want 'userPatch' instead of 'patch' in update
       * mutations.
       */
      //pgSimplifyPatch: false,
      /*
       * Uncomment if you want 'allUsers' instead of 'users' at root level.
       */
      //pgSimplifyAllRows: false,
    },
    // ... other settings ...
  })
);

Naming your foreign key fields

By naming your foreign key along the lines of author_id or author_fk, e.g.:

CREATE TABLE posts (
  id serial primary key,
  author_id int not null references users,
  ...
);

We can automatically extract the field prefix: author and call the relation author rather than the default: user. This allows for a post to have an author, editor, reviewer, etc. all which point to users.

The reverse, however, is not so easy. On the User type, we can't call the reverse of all these different relations posts. The default inflector refers to these as postsByAuthorId, postsByEditorId, etc. However we'd rather use shorter names, so we introduce a new inflector: getOppositeBaseName. This inflector is passed a baseName (the part without the _id/_fk suffix, e.g. author, editor, reviewer above) and should return the opposite of that base name which will be prepended to the target type to produce, e.g. authoredPosts, editedPosts, reviewedPosts. Failing this, we just fall back to the default inflector; it will be up to you to add smart comments or a custom inflector to override these.

Handling field conflicts:

In most cases, the conflict errors will guide you on how to fix these issues using smart comments.