> For the complete documentation index, see [llms.txt](https://docs.ember-cli-typescript.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.ember-cli-typescript.com/ember-data/transforms.md).

# Transforms

In Ember Data, `attr` defines an attribute on a [Model](https://guides.emberjs.com/release/models/defining-models/). By default, attributes are passed through as-is, however you can specify an optional type to have the value automatically transformed. Ember Data ships with four basic transform types: `string`, `number`, `boolean` and `date`.

You can define your own transforms by subclassing [Transform](https://guides.emberjs.com/release/models/defining-models/#toc_custom-transforms). Ember Data transforms are normal TypeScript classes. The return type of `deserialize` method becomes type of the model class property.

You may define your own transforms in TypeScript like so:

```typescript
# app/transforms/coordinate-point.ts
import Transform from '@ember-data/serializer/transform';

declare module 'ember-data/types/registries/transform' {
  export default interface TransformRegistry {
    'coordinate-point': CoordinatePointTransform;
  }
}

export type CoordinatePoint = {
  x: number;
  y: number;
};

export default class CoordinatePointTransform extends Transform {
  deserialize(serialized): CoordinatePoint {
    return { x: value[0], y: value[1] };
  }

  serialize(value): number {
    return [value.x, value.y];
  }
}

# app/models/cursor.ts
import Model, { attr } from '@ember-data/model';
import { CoordinatePoint } from 'agwa-data/transforms/coordinate-point';

declare module 'ember-data/types/registries/model' {
  export default interface ModelRegistry {
    cursor: Cursor;
  }
}

export default class Cursor extends Model {
  @attr('coordinate-point') declare position: CoordinatePoint;
}
```

Note that you should declare your own transform under `TransformRegistry` to make `attr` to work with your transform.


---

# Agent Instructions
This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com.

## Querying This Documentation
If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter, and the optional `goal` query parameter:

```
GET https://docs.ember-cli-typescript.com/ember-data/transforms.md?ask=<question>&goal=<endgoal>
```

`ask` is the immediate question: it should be specific, self-contained, and written in natural language.
`goal` is optional and describes the broader end goal you are ultimately trying to accomplish on behalf of the user. GitBook uses it to tailor the answer towards what is most useful for that goal.

The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.