litedbmodel-gen

embedoc-based model code generator for litedbmodel. Parses SQL DDL (PostgreSQL / MySQL / SQLite) and generates TypeScript column definitions that stay in sync with your schema.

How It Works

litedbmodel-gen provides two embedoc plugins:

1. Custom Datasource (sql_schema) — reads and parses a schema.sql file into structured table definitions
2. Renderer (litedbmodel_columns) — generates @column() decorator code from the datasource

Using embedoc's in-place marker system, only the column definitions inside markers are auto-updated. Hand-written code (relations, custom methods, exports) outside the markers is preserved.

@model('users')
class UserModel extends DBModel {
  /*@embedoc:litedbmodel_columns table="users"*/
  @column({ primaryKey: true }) id?: number;
  @column() name?: string;
  @column() email?: string | null;
  @column.boolean() is_active?: boolean | null;
  @column.datetime() created_at?: Date;
  @column.datetime() updated_at?: Date;
  /*@embedoc:end*/

  // Hand-written — not touched by embedoc
  @hasMany(() => [User.id, Post.user_id])
  declare posts: Promise<Post[]>;
}

export const User = UserModel.asModel();
export type User = InstanceType<typeof User>;

Quick Start

1. Initialize embedoc in your project

npx embedoc init

2. Install litedbmodel-gen

npm install -D litedbmodel-gen

3. Run the init command

npx litedbmodel-gen init

This automatically:

• Copies the Handlebars template to .embedoc/templates/model.hbs
• Registers the sql_schema datasource in .embedoc/datasources/index.ts
• Registers the litedbmodel_columns renderer in .embedoc/renderers/index.ts
• Adds a schema datasource config to embedoc.config.yaml
• Adds ./models/**/*.ts to the build targets

If your config file is not at the default embedoc.config.yaml:

npx litedbmodel-gen init path/to/embedoc.config.yaml

4. Edit the config

Open embedoc.config.yaml and set the schema path and database dialect:

datasources:
  schema:
    type: sql_schema
    path: "./db/schema.sql"       # your DDL file
    database: PostgreSQL           # PostgreSQL | MySQL | SQLite
    generators:
      - output_path: "./models/{model_class}.ts"
        template: model.hbs
        overwrite: false

5. Generate and build

# Create model files for each table
npx embedoc generate --datasource schema

# Fill in column definitions
npx embedoc build

# Or use watch mode for ongoing sync
npx embedoc watch

Workflow

schema.sql changes
      |
      v
embedoc build / watch
      |
      +-- existing models/*.ts
      |     column definitions inside markers are updated
      |     relations and exports are preserved
      |
      +-- new tables
            embedoc generate --datasource schema
            creates new model files from template
            embedoc build fills in column definitions

Supported SQL Types

Common (all dialects)

| SQL Type | Decorator | TypeScript Type | |----------|-----------|-----------------| | INTEGER, INT, SMALLINT, SERIAL | @column() | number | | BIGINT, BIGSERIAL | @column.bigint() | bigint | | NUMERIC, DECIMAL, REAL, FLOAT, DOUBLE PRECISION | @column() | number | | VARCHAR, TEXT, CHAR | @column() | string | | BOOLEAN | @column.boolean() | boolean | | TIMESTAMP, TIMESTAMPTZ, DATETIME | @column.datetime() | Date | | DATE | @column.date() | Date | | JSON, JSONB | @column.json<Record<string, unknown>>() | Record<string, unknown> | | UUID | @column.uuid() | string |

PostgreSQL Arrays

| SQL Type | Decorator | TypeScript Type | |----------|-----------|-----------------| | TEXT[] | @column.stringArray() | string[] | | INTEGER[] | @column.intArray() | number[] | | NUMERIC[] | @column.numericArray() | (number \| null)[] | | BOOLEAN[] | @column.booleanArray() | (boolean \| null)[] | | TIMESTAMP[] | @column.datetimeArray() | (Date \| null)[] |

MySQL-specific

| SQL Type | Decorator | TypeScript Type | |----------|-----------|-----------------| | TINYINT(1) | @column.boolean() | boolean |

Primary Keys

Columns with PRIMARY KEY constraints use @column({ primaryKey: true }). For UUID primary keys: @column.uuid({ primaryKey: true }). Composite primary keys are supported.

Marker Syntax

Inside your model class:

/*@embedoc:litedbmodel_columns table="TABLE_NAME"*/
// auto-generated column definitions
/*@embedoc:end*/

If your datasource is not named schema, specify it:

/*@embedoc:litedbmodel_columns table="users" datasource="my_schema"*/

CLI

# Initialize litedbmodel-gen in an embedoc project
npx litedbmodel-gen init [config-path]

API

The package also exports lower-level utilities:

import {
  sqlSchema,            // embedoc custom datasource
  litedbmodelColumns,   // embedoc renderer
  parseSchema,          // SQL DDL parser
  generateColumnCode,   // code generator
  mapColumnType,        // single column type mapper
} from 'litedbmodel-gen';

parseSchema(sql, options?)

Parses SQL DDL and returns table definitions.

const tables = parseSchema(sql, { database: 'PostgreSQL' });
// Returns: TableDef[] = [{ name: string, columns: ColumnDef[] }]

Requirements

• Node.js 18+
• embedoc >= 0.11.0

License

MIT