async-hooks-2.js

const fs = require('fs');
const async_hooks = require('async_hooks');
async_hooks.createHook({
   init(asyncId, type, triggerAsyncId) {
      fs.writeSync(1, `Init ${type} resource: asyncId: ${asyncId} trigger: ${triggerAsyncId}\n`);
   },
   destroy(asyncId) {
      const eid = async_hooks.executionAsyncId();
      fs.writeSync(1, `Destroy resource: execution: ${eid} asyncId: ${asyncId}\n`);
  }
}).enable();


const eid = async_hooks.executionAsyncId();
fs.writeSync(1, `Calling setTimeout: execution: ${eid}\n`);
setTimeout(() => {
   const eid = async_hooks.executionAsyncId();
   fs.writeSync(1, `Inside setTimeout: execution: ${eid}\n`);
}, 0);