At any point before or during the , reply.hijack() can be called to prevent Fastify from:

    • Running all the following hooks and user handler
    • Sending the response automatically

    Reply Lifecycle

    Whenever the user handles the request, the result may be:

    • in async handler: it returns a payload
    • in async handler: it throws an Error
    • in sync handler: it sends a payload
    • in sync handler: it sends an Error instance
    2.                                     └─▶ schemaErrorFormatter
    3.                                                │
    4.                           reply sent ◀── JSON ─┴─ Error instance
    5.                                                       │
    6.                                                       │         ★ throw an Error
    7.                      ★ send or return                 │                 │
    8.                             │                         ▼                 │
    9.        reply sent ◀── JSON ─┴─ Error instance ──▶ setErrorHandler ◀─────┘
    10.                                                       │
    11.                                  reply sent ◀── JSON ─┴─ Error instance ──▶ onError Hook
    12.                                                                                 │
    13.                                                                                 └─▶ reply sent

    Note: means that the JSON payload will be serialized by:

    • the if set
    • or by the default JSON.stringify function