# schema-format-defined

Source: https://apigenie.pl/docs/linter/asyncapi/rules/schema-format-defined

This rule ensures that numeric schemas specify the precision of their values
with a `format`.

## Rule Details

JSON Schema does not limit the size or the precision of numbers. Without a
`format`, code generators and consumers written in strongly typed languages
have to guess which native type to use, which often leads to overflows or to
lost precision.

The `schema-format-defined` rule checks every schema of an AsyncAPI document
and reports:

- `Schema with integer type does not define proper format` when a schema of
  type `integer` does not have the `int32` or `int64` format,
- `Schema with number type does not define proper format` when a schema of
  type `number` does not have the `float` or `double` format.

## Configuration

None.

## Examples

**Good**.

```yaml
asyncapi: 3.0.0
info:
  title: Order Events
  version: 1.0.0
components:
  schemas:
    OrderPlaced:
      type: object
      properties:
        quantity:
          type: integer
          format: int32
        total:
          type: number
          format: double
```

**Bad**.

```yaml
asyncapi: 3.0.0
info:
  title: Order Events
  version: 1.0.0
components:
  schemas:
    OrderPlaced:
      type: object
      properties:
        quantity:
          type: integer
        total:
          type: number
          format: decimal
```

## When Not to Use It

You may disable this rule if your messages are consumed only by clients
written in dynamically typed languages, where the precision of numbers does
not matter.

## Compatibility

This rule is compatible with AsyncAPI 3.x documents. AsyncAPI 2.x documents
are rejected by the reader and are not linted.