async_hooks_promises.js

const hooks = require('async_hooks')

const promises = new Set()

const hook = hooks.createHook({
  init (asyncId, type) {
    if (type === 'PROMISE') {
      promises.add(asyncId)
    }
  },
  after (asyncId) {
    promises.delete(asyncId)
  },
  destroy (asyncId) {
    promises.delete(asyncId)
  }
})

hook.enable()

function wait () {
  return new Promise(function (resolve) {
    setTimeout(resolve, 100)
  })
}

async function foo () {
  await wait()
  await wait()
}

foo()

setTimeout(function () {
  hook.disable()
  console.log('promises.size', promises.size)
}, 500)