Model Mixins

Powerful model enhancement system that extends functionality with reusable, composable patterns

Model mixins extend your database models with powerful behaviors and utilities. Built on a functional composition pattern, mixins allow you to easily combine multiple enhancements together to create more specialized models.

Available Mixins

Double Tie Query Builder provides the following built-in mixins:

Mixin	Description
`withAssignProperties`	Creates model instances with data assignment capabilities
`withCreatedAt`	Automatically adds timestamps when records are created
`withUpdatedAt`	Automatically updates timestamps when records are modified
`withGlobalId`	Adds global ID functionality for GraphQL-friendly identifiers
`withIdGenerator`	Generates unique IDs with custom prefixes
`withSlug`	Creates and manages URL-friendly slugs
`withCursorable`	Adds cursor-based pagination for efficient list traversal

Composing Mixins

Mixins can be combined using functional composition to create models with multiple enhanced behaviors:

import { createDatabase, createModel } from '@doubletie/query-builder';
import {
  withUpdatedAt,
  withSlug,
  withIdGenerator
} from '@doubletie/query-builder/mixins';
 
// Create a base model
const db = createDatabase<Database>(/* config */);
const baseModel = createModel(db, 'posts', 'id');
 
// Apply multiple mixins with composition
const PostModel = withUpdatedAt(
  withSlug(
    withIdGenerator(baseModel, { prefix: 'post' }),
    'slug',
    'title'
  ),
  'updatedAt'
);
 
// Now PostModel has all three behaviors
const post = await PostModel.insertWithGeneratedId({
  title: 'Hello World',
  content: 'This is my first post'
}); // Has ID, slug, and timestamps

Creating Custom Mixins

You can create your own custom mixins by following the functional enhancement pattern:

function withCustomBehavior<
  TDatabase,
  TTableName extends keyof TDatabase & string,
  TIdColumnName extends keyof TDatabase[TTableName] & string
>(model: ModelFunctions<TDatabase, TTableName, TIdColumnName>) {
  return {
    ...model,
    
    // Add new methods
    customMethod() {
      // Implementation
    },
    
    // Override existing methods
    findById: async (id, ...args) => {
      console.log(`Finding record with ID: ${id}`);
      return model.findById(id, ...args);
    }
  };
}

Model Mixins

Available Mixins

Composing Mixins

Creating Custom Mixins

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