Kanel extension to generate enum types from table values

This package extends Kanel with the ability to generate enum types from table values.

It uses the Postgraphile concept of enum tables.

Smart Comments

Mark a table as an enum table by adding a @enum tag to its comment:

COMMENT ON TABLE animal_type IS '@enum';

You can optionally rename the generated type with @enumName:

COMMENT ON TABLE animal_type IS E'@enum\n@enumName TypeOfAnimal';

Both Postgraphile's space format and the colon format used by other Kanel extensions are supported:

• @enumName TypeOfAnimal (Postgraphile convention)
• @enumName:TypeOfAnimal (tagged-comment-parser convention)

@enumDescription

You can add per-value descriptions to your enum by tagging a column with @enumDescription. The values in that column will be rendered as JSDoc comments on each enum member.

CREATE TABLE animal_type (
  type text PRIMARY KEY,
  description text NOT NULL
);

COMMENT ON TABLE animal_type IS '@enum';
COMMENT ON COLUMN animal_type.description IS '@enumDescription';

INSERT INTO animal_type VALUES
  ('cat', 'A small domesticated feline'),
  ('dog', 'A loyal canine companion');

With enumStyle: "enum" this generates:

export enum AnimalType {
  /** A small domesticated feline */
  cat = "cat",
  /** A loyal canine companion */
  dog = "dog",
}

With enumStyle: "type" (the default) this generates:

export type AnimalType =
  /** A small domesticated feline */
  | "cat"
  /** A loyal canine companion */
  | "dog";

Installation

Assuming you already have Kanel installed, add this with

npm i -D kanel-enum-tables

Usage

Add the hook to your .kanelrc.js file:

const { enumTablesPreRenderHook } = require("kanel-enum-tables");

module.exports = {
  // ... your config here.

  preRenderHooks: [enumTablesPreRenderHook],
};

With kanel-kysely

When using kanel-kysely, place enumTablesPreRenderHook before the kysely hook for best results:

const { enumTablesPreRenderHook } = require("kanel-enum-tables");
const { makeKyselyHook } = require("kanel-kysely");

module.exports = {
  // ... your config here.

  preRenderHooks: [enumTablesPreRenderHook, makeKyselyHook()],
};

The hook also works if placed after the kysely hook — it will detect the ColumnType<> wrappers and update them accordingly.