### AsyncAPI Schema Example

Source: https://github.com/waleedashraf/asyncapi-validator/blob/master/README.md

An example AsyncAPI v3.0.0 schema defining channels, messages, and schemas, used for message validation.

```yaml
asyncapi: 3.0.0
info:
  title: Streetlights Kafka API
  version: 1.0.0
channels:
  lightingMeasured:
    messages:
      lightMeasured:
        $ref: '#/components/messages/lightMeasured'
operations:
  sendLightMeasurement:
    action: send
    channel:
      $ref: '#/channels/lightingMeasured'
    messages:
      - $ref: '#/channels/lightingMeasured/messages/lightMeasured'
components:
  messages:
    lightMeasured:
      x-unique-id: lightMeasured
      payload:
        $ref: '#/components/schemas/lightMeasuredPayload'
  schemas:
    lightMeasuredPayload:
      type: object
      properties:
        lumens:
          type: integer
          minimum: 0
          description: Light intensity measured in lumens.
```

--------------------------------

### Example Usage: Validate Method

Source: https://github.com/waleedashraf/asyncapi-validator/blob/master/README.md

Demonstrates how to use the `.validate()` method after loading an AsyncAPI schema from a YAML file. It shows setting the `msgIdentifier` and then validating a specific message.

```javascript
const AsyncApiValidator = require('asyncapi-validator')
let va = await AsyncApiValidator.fromSource('./api.yaml', {msgIdentifier: 'x-unique-id'})

// validate 'lightMeasured' on channel 'lightingMeasured' with operation 'send'
va.validate('lightMeasured', {
  lumens: 0,
  sentAt: '2019-08-24T14:15:22Z'
}, 'lightingMeasured', 'send')
```

--------------------------------

### AsyncAPI Validation Error Structure

Source: https://github.com/waleedashraf/asyncapi-validator/blob/master/README.md

Illustrates the structure of errors returned by the `asyncapi-validator` library. Errors include a name, key, and an array of detailed validation issues, often originating from AJV.

```javascript
{
  AsyncAPIValidationError: data.type must be equal to one of the allowed values at MessageValidator.validate (.....
  name: 'AsyncAPIValidationError',
  key: 'hello',
  errors:
    [
      {
        keyword: 'enum',
        dataPath: '.type',
        schemaPath: '#/properties/type/enum',
        params: [Object],
        message: 'must be equal to one of the allowed values'
      }
    ]
}

```

--------------------------------

### Load AsyncAPI Schema from Source

Source: https://github.com/waleedashraf/asyncapi-validator/blob/master/README.md

Loads and parses an AsyncAPI schema from a given source (local path, URL, or object). It accepts options for validation, such as specifying a message identifier or ignoring array validation.

```javascript
/** 
 * Load and Parse the schema from source.
 * @param {string | Object} source - local PATH or URL of schema or schema Object
 * @param {Object} options - options for validation
 * @returns {Promise}
 */
AsyncApiValidator.fromSource(source, options)
```

--------------------------------

### Validate Message by ID with AsyncAPI Schema

Source: https://github.com/waleedashraf/asyncapi-validator/blob/master/README.md

Demonstrates how to load an AsyncAPI schema from a file and validate a message payload against a specific message ID ('UserRemoved'). This requires the `asyncapi-validator` library and a valid AsyncAPI schema file.

```yaml
asyncapi: 2.4.0

info:
  title: User Events
  version: 1.0.0

channels:
  user-events:
    description: user related events
    publish:
      message:
        messageId: UserRemoved
        payload:
          type: object
          properties:
            userEmail:
              type: string
            userId:
              type: string

```

```javascript
const AsyncApiValidator = require('asyncapi-validator')
let va = await AsyncApiValidator.fromSource('./api.yaml')

// validate messageId 'UserRemoved'
va.validateByMessageId('UserRemoved', {
  userId: '123456789',
  userEmail: 'alex@mail.com',
})

```

--------------------------------

### Access Resolved AsyncAPI Schema

Source: https://github.com/waleedashraf/asyncapi-validator/blob/master/README.md

The `.schema` property provides access to the AsyncAPI schema in JSON format, with all internal references resolved.

```javascript
`.schema` property can be used to access AsyncApi schema in JSON format and with all the refs resolved.
```

--------------------------------

### Validate Message Payload

Source: https://github.com/waleedashraf/asyncapi-validator/blob/master/README.md

Validates a message payload against the AsyncAPI schema definition. Requires a message key (derived from `msgIdentifier`), the payload object, channel name, and operation type (publish/subscribe/send/receive).

```javascript
/**
 * Method to validate the Payload against schema definition.
 * @param {string} key - required - message key (as per msgIdentifier)
 * @param {Object} payload - required - payload of the message
 * @param {string} channel - required - name of the channel/topic
 * @param {string} operation - required - publish | subscribe | send | receive
 * @returns {boolean}
 */
.validate(key, payload, channel, operation)
```

--------------------------------

### Validate Message by Message ID (Deprecated)

Source: https://github.com/waleedashraf/asyncapi-validator/blob/master/README.md

Validates a message payload using a message ID. This method is deprecated due to the removal of `messageId` in AsyncAPI v3.0.0. It requires the AsyncAPI schema version to be between v2.4.0 and v3.0.0.

```javascript
/**
 * Method to validate the Payload against schema definition.
 * @param {string} key - required - messageId
 * @param {Object} payload - required - payload of the message
 * @returns {boolean}
 */
.validateByMessageId(key, payload)
```

=== COMPLETE CONTENT === This response contains all available snippets from this library. No additional content exists. Do not make further requests.