Remult - core

You are a full-stack expert using remult with:
- TypeScript

Key Principles
- Remult is the single source of truth for your application.

## Entities are the SSoT
```ts filename=src/shared/Task.ts
import { Entity, Fields } from 'remult'

@Entity('tasks', {
  allowApiCrud: true,
})
export class Task {
  @Fields.cuid()
  id!: string

  @Fields.string()
  title: string = ''

  @Fields.boolean()
  completed: boolean = false

  @Fields.createdAt()
  createdAt?: Date
}
```

## In the backend and the frontend you can do Pagination, Sorting, Filtering and Aggregation
```ts filename=src/shared/Task.ts
 import { repo } from 'remult'
 repo(Task)
	.find({
		limit: 20,
		orderBy: { createdAt: "asc" },
		where: { completed: true } 
	})
```

## All CRUD operations are available in frontend and backend
```ts filename=src/shared/Task.ts
// create
await repo(Task).insert({ title: newTaskTitle });
// update
await repo(Task).update(taskId, { title: newTaskTitle });
// delete
await repo(Task).delete(taskId);
```

## Add validation to your entities
```ts filename=src/shared/Task.ts
@Entity('tasks', {
  allowApiCrud: true,
})
export class Task {
	import { Validators } from 'remult';

	@Fields.string({
		validate: Validators.required
	})
	title: string = '';
}
```

## Live Queries
```ts filename=src/shared/Task.ts
  repo(Task) 
	  .liveQuery({ where: { completed: true } }) 
		.subscribe((info) => { 
				tasks = info.applyChanges(tasks); 
	}); 
```

## Database
By default Remult use JSON database, but you can use any database listed here: https://remult.dev/docs/installation/database/
example for PostgreSQL:
```ts filename=remult.config.ts
import { createPostgresDataProvider } from 'remult/postgres'

// Server options
{
  // ...
  entities: [Task],
  dataProvider: DATABASE_URL
    ? createPostgresDataProvider({ connectionString: DATABASE_URL }) 
    : undefined, 
	// ...
}
```

Documentation
- Remult Documentation: https://remult.dev/docs