Lodash import reported as an open handle by jest --detectOpenHandles

[cynicaloptimist]

Not sure how to troubleshoot this. When running jest the test runner succeeds, but reports

Jest did not exit one second after the test run has completed.

This usually means that there are asynchronous operations that weren't stopped in your tests. Consider running Jest with `--detectOpenHandles` to troubleshoot this issue.

Running jest --detectOpenHandles Encounter reports the following:

 PASS  client\test\Encounter.test.ts
  Encounter
    √ A new Encounter has no combatants (16ms)
    ○ skipped 3 tests

Test Suites: 1 passed, 1 total
Tests:       3 skipped, 1 passed, 4 total
Snapshots:   0 total
Time:        3.479s
Ran all test suites matching /Encounter/i.

Jest has detected the following 2 open handles potentially keeping Jest from exiting:

  ●  PROMISE

    > 1 | import * as _ from "lodash";
        | ^
      2 |
      3 | export interface KeyValueSet<T> {
      4 |     [key: string]: T;

          at Function.resolve (<anonymous>)
      at runInContext (node_modules/lodash/lodash.js:6069:36)
      at Object.<anonymous> (node_modules/lodash/lodash.js:17078:11)
      at Object.<anonymous> (node_modules/lodash/lodash.js:17105:3)
      at Object.<anonymous> (common/Toolbox.ts:1:1)


  ●  PROMISE

          at Function.resolve (<anonymous>)
      at Object.<anonymous> (node_modules/lodash.reduce/index.js:1589:32)
      at Object.<anonymous> (node_modules/react-string-replace-recursively/lib/substituteHelper.js:5:14)

[reggi]

I'm getting this issue as well :(

[reggi]

These errors are kind of a bummer.

I may have a leak or some run-on process but I can't find it...

[CrisTowi]

I am having the same issue. Have you found any solution for this?

[cynicaloptimist]

I haven't figured this out, might be time to cross post this to StackOverflow.

[robmcguinness]

I had the same issue. I "fixed" the issue by importing individual lodash components instead of the entire lib.

[anandnimkar]

I'm having this issue in a completely separate repo. If you've figured this out, can you post a solution here or on StackOverflow?

[prevostc]

Same issue for me :s

[cynicaloptimist]

Importing individual lodash components works for Toolbox.ts, but Encounter.ts still warns:

Jest has detected the following 2 open handles potentially keeping Jest from exiting:

  ●  PROMISE

      1 | import * as ko from "knockout";
    > 2 | import { max, sortBy } from "lodash";

---

[brunoMaurice]

Got the same issue using nock :

●  PROMISE

      at Function.resolve (<anonymous>)
      at runInContext (node_modules/lodash/lodash.js:6069:36)
      at Object.<anonymous> (node_modules/lodash/lodash.js:17078:11)
      at Object.<anonymous> (node_modules/lodash/lodash.js:17105:3)
      at Object.<anonymous> (node_modules/nock/lib/common.js:3:9)

[alexturek]

I'm getting this issue across multiple versions of lodash, and the linked lines go to Promise.resolve() calls:

Errors from Jest

  ●  PROMISE

          at Function.resolve (<anonymous>)
      at Object.<anonymous> (node_modules/lodash.omitby/index.js:1576:32)

  ●  PROMISE

          at Function.resolve (<anonymous>)
      at runInContext (node_modules/private/dependency/node_modules/lodash/lodash.js:5975:36)

  ●  PROMISE

      1 | "use strict";
      2 | Object.defineProperty(exports, "__esModule", { value: true });
    > 3 | const _ = require("lodash");
        |           ^
      4 | const errors = require("./errors");
      5 | const codeToErrorMap = {};
      6 | for (const errorType of _.values(errors)) {

          at Function.resolve (<anonymous>)
      at runInContext (node_modules/lodash/lodash.js:6069:36)
      at Object.<anonymous> (node_modules/lodash/lodash.js:17078:11)
      at Object.<anonymous> (node_modules/lodash/lodash.js:17105:3)

Linked line from lodash

Both lodash lines resolve to this

     // Fallback for data views, maps, sets, and weak maps in IE 11 and promises in Node.js < 6.
     if ((DataView && getTag(new DataView(new ArrayBuffer(1))) != dataViewTag) ||
         (Map && getTag(new Map) != mapTag) ||
+        (Promise && getTag(Promise.resolve()) != promiseTag) ||
         (Set && getTag(new Set) != setTag) ||
         (WeakMap && getTag(new WeakMap) != weakMapTag)) {
       getTag = function(value) {
         var result = objectToString.call(value),
             Ctor = result == objectTag ? value.constructor : undefined,
             ctorString = Ctor ? toSource(Ctor) : undefined;

Open handles from wtfnode

[WTF Node?] open handles:
- File descriptors: (note: stdio always exists)
  - fd 1 (tty) (stdio)
  - fd 2 (tty) (stdio)
- Sockets:
  - 127.0.0.1:58344 -> 127.0.0.1:9050
    - Listeners:
      - connect: Object.<anonymous>.Connection.connect @ /Users/aturek/service/node_modules/pg/lib/connection.js:58
  - (?:?) -> localhost:? (destroyed)
- Timers:
  - (1000 ~ 1000 ms) (anonymous) @ /Users/aturek/service/node_modules/pg-pool/node_modules/generic-pool/lib/generic-pool.js:247
Unable to determine callsite for "Function". Did you require `wtfnode` at the top of your entry point?
  - (1000 ~ 1000 ms) (anonymous) @ unknown:0
Unable to determine callsite for "Function". Did you require `wtfnode` at the top of your entry point?
  - (100 ~ 100 ms) (anonymous) @ unknown:0

[jdalrymple]

Importing singular lodash libraries works for lodash, but what about other libraries :( ?

[alexturek]

I think this is a bug with jest, and I've filed an issue https://github.com/facebook/jest/issues/6639