fastify/lib/wrapThenable.js

'use strict'

const {
  kReplyIsError,
  kReplySent,
  kReplySentOverwritten
} = require('./symbols')

const { FST_ERR_PROMISE_NOT_FULLFILLED } = require('./errors')

function wrapThenable (thenable, reply) {
  thenable.then(function (payload) {
    if (reply[kReplySentOverwritten] === true) {
      return
    }

    // this is for async functions that
    // are using reply.send directly
    if (payload !== undefined || (reply.raw.statusCode === 204 && reply[kReplySent] === false)) {
      // we use a try-catch internally to avoid adding a catch to another
      // promise, increase promise perf by 10%
      try {
        reply.send(payload)
      } catch (err) {
        reply[kReplySent] = false
        reply[kReplyIsError] = true
        reply.send(err)
      }
    } else if (reply[kReplySent] === false) {
      reply.log.error({ err: new FST_ERR_PROMISE_NOT_FULLFILLED() }, "Promise may not be fulfilled with 'undefined' when statusCode is not 204")
    }
  }, function (err) {
    if (reply[kReplySentOverwritten] === true) {
      reply.log.error({ err }, 'Promise errored, but reply.sent = true was set')
      return
    }
    reply[kReplySent] = false
    reply[kReplyIsError] = true
    reply.send(err)
  })
}

module.exports = wrapThenable