kysely-pgschema

Generate Kysely type definitions from PostgreSQL schema files — no database connection required.

Parses .sql files offline using the official PostgreSQL parser (libpg-query, compiled to WASM).

Installation

npm install --save-dev kysely-pgschema

Usage

kysely-pgschema --schema ./db/schema.sql --out-file ./src/db/types.d.ts

Given this schema:

CREATE TYPE user_role AS ENUM ('admin', 'member');

CREATE TABLE users (
  id         serial PRIMARY KEY,
  email      text NOT NULL,
  role       user_role NOT NULL DEFAULT 'member',
  created_at timestamptz NOT NULL DEFAULT now(),
  deleted_at timestamptz
);

Generates:

import type { ColumnType } from 'kysely';

export type Generated<T> = ...;
export type Timestamp = ColumnType<Date, Date | string, Date | string>;

export type UserRole = 'admin' | 'member';

export interface Users {
  id: Generated<number>;
  email: string;
  role: Generated<UserRole>;
  created_at: Generated<Timestamp>;
  deleted_at: Timestamp | null;
}

export interface DB {
  users: Users;
}

Then use it with Kysely:

import { Kysely, PostgresDialect } from 'kysely';
import { DB } from './types.d.ts';

const db = new Kysely<DB>({ dialect: ... });

\i includes

Schema files that use \i (e.g. from pgschema.com or pg_dump splits) are resolved recursively:

-- schema.sql
\i ./tables/users.sql
\i ./tables/posts.sql

CLI options

| Flag | Default | Description | |---|---|---| | --schema | required | Path to SQL schema file | | --out-file | kysely-pgschema.d.ts | Output file path | | --camel-case | false | Convert snake_case columns to camelCase | | --default-schema | public | Schema used as root in the DB interface | | --include-pattern | — | Glob to include only matching schema.table | | --exclude-pattern | — | Glob to exclude matching schema.table | | --date-parser | timestamp | timestamp or string for date/time columns | | --numeric-parser | string | string, number, or number-or-string | | --runtime-enums | false | Also emit const objects for enum types | | --nullability | null | null (T \| null), optional (field?: T), or undefined (T \| undefined) | | --config-file | auto | Path to config file |

Config file

Options can also be set in .kysely-pgschemarc.json:

{
  "schema": "./db/schema.sql",
  "outFile": "./src/db/types.d.ts",
  "camelCase": true,
  "runtimeEnums": true,
  "nullability": "optional"
}

Supported SQL statements

• CREATE TABLE
• CREATE TYPE ... AS ENUM
• ALTER TABLE ... ADD COLUMN
• ALTER TABLE ... ALTER COLUMN SET NOT NULL / DROP NOT NULL / SET DEFAULT

Development

npm test          # run tests (node:test)
npm run typecheck # tsc --noEmit
npm run build     # compile to dist/