async-hooks-promise-catch.js

// map will store all the stack traces recorded at init().
var map = new Map();

var async_hooks = require('async_hooks');
async_hooks.createHook({ init }).enable();

function init(id, type, parentId) {
  const obj = {};
  // Capture the stack trace, omitting the call to init().
  Error.captureStackTrace(obj, init);
  // Store the stack trace and parentId. The later will be used to retrieve
  // the stack from the parent call.
  map.set(id, [obj.stack, parentId, async_hooks.currentId()]);
}


var p = new Promise(function f1() {
  (function foo() { throw new Error() })();
});

var p2 = (function q1() {
  return p.catch(function f2() {
    (function bar() { throw new Error() })();
  })
})();

p2.catch(genStack);


function genStack() {
  var cid = async_hooks.currentId();
  var item;
  console.log(new Error().stack.substr(6));
  do {
    item = map.get(cid);
    console.log(item[0]);
    // Swap item[1] for item[2] to see stack based on currentId()
    cid = item[1];
  } while (cid > 0);
}


// parentId stack:
//   genStack
//   bar
//   f2
//   foo
//   f1
//   <anonymous>


// currentId stack:
//   genStack
//   <anonymous>

// But the two can be mixed/matched to get different stacked. e.g.:
//   genStack
//   bar
//   f2
//   q1
//   <anonymous>