Uncaught Error: Zone already loaded

[CanKer]

I don't really know how it happened but I got the "Uncaught Error: Zone already loaded" error in my console after doing some POST petitions. The functionality it's ok, but the look of the app it changes.

[hctomkins]

+1

[AGoodnight]

Make sure your not loading the module twice, I had it hiding in my index file:

...
<script src="node_modules/zone.js/dist/zone.js"></script>  // <-- I removed this
...

Incidentally if you load it more than once you screw up the router a bit. You need to click your routing links multiple times when this bug arises after loading it too many times.

[jgf5013]

EDIT: The problem was actually that I was including the script twice. Actually, I was including another script (which had zone as a dependency) twice.

[hctomkins]

It was the same with me. If this happening to you, try removing where you include zone.js from your index.html

[Splaktar]

This looks like a project configuration issue rather than a Zone.js bug. That said, the error message could be more helpful. It should specify the name of the zone that is already loaded or some identifying information. In my case, the stack trace pointed to three different source files in my code, none of which were really helpful.

For me, this ended up being an issue with my Polymer dependencies from Bower. If I am missing a Polymer dependency, then this error occurs saying Uncaught Error: Zone already loaded. Fixing my bower.json and my imports in elements.html resolved the error.

[gandra]

Angular has a terrible debug feedback ... zone not loaded ... thank you very much!

Look at the quality of provided info (this is my case) ... all test pass ok, build pass ok, deploy pass and in the runtime I found this:

Uncaught Error: Zone already loaded.
    at /vendor.bundle.js:129468:15 [<root>]
    at /vendor.bundle.js:130572:3 [<root>]
    at NO_ZONE.name (vendor.bundle.js:129454) [<root>]
    at Object.<anonymous> (vendor.bundle.js:129457) [<root>]
    at Object.<anonymous> (vendor.bundle.js:131514) [<root>]
    at __webpack_require__ (inline.bundle.js:53) [<root>]
    at Object.378 (main.bundle.js:2231) [<root>]
    at __webpack_require__ (inline.bundle.js:53) [<root>]
    at Object.343 (main.bundle.js:235) [<root>]
    at __webpack_require__ (inline.bundle.js:53) [<root>]
    at Object.824 (main.bundle.js:3100) [<root>]
    at __webpack_require__ (inline.bundle.js:53) [<root>]
    at webpackJsonpCallback (inline.bundle.js:24) [<root>]
    at /main.bundle.js:1:1 [<root>]

[JiaLiPassion]

Thank you for all the information , I will try to make the error message more helpful.

[gandra]

Kudos to @JiaLiPassion for attitude!

[JiaLiPassion]

@gandra , thank you!!

[rgbsuede]

Hmmm

vendor.js:124539 Uncaught Error: Zone already loaded.
    at vendor.js:124539
    at vendor.js:125151
    at FUNCTION (vendor.js:124516)
    at Object.<anonymous> (vendor.js:124519)
    at Object.<anonymous> (vendor.js:127569)
    at __webpack_require__ (vendor.js:55)
    at Object.<anonymous> (vendor.js:77767)
    at __webpack_require__ (vendor.js:55)
    at Object.<anonymous> (vendor.js:124034)
    at __webpack_require__ (vendor.js:55)

[herkulano]

Also getting this error running tests

  ● Test suite failed to run

    Zone already loaded.

    > 6 | import { Observable } from 'rxjs'

[leandrocodes]

Error: Zone already loaded.
at http://localhost:8100/build/vendor.js:126384:15
at http://localhost:8100/build/vendor.js:126996:3
at FUNCTION (http://localhost:8100/build/vendor.js:126361:10)
at Object. (http://localhost:8100/build/vendor.js:126364:2)
at Object. (http://localhost:8100/build/vendor.js:129414:30)
at webpack_require (http://localhost:8100/build/vendor.js:55:30)
at Object.__extends (http://localhost:8100/build/vendor.js:76999:66)
at webpack_require (http://localhost:8100/build/vendor.js:55:30)
at Object. (http://localhost:8100/build/vendor.js:126083:72)
at webpack_require (http://localhost:8100/build/vendor.js:55:30)

[guillop]

fix:
npm install angularfire2@5.0.0-rc.4

[rahuljograna]

This is the problem of new firebase update, here is a solution for this error

** Step: 1** Install the lower version of firebase using this command

npm install angularfire2@5.0.0-rc.4

** Step: 2**

npm install

Try.

[lavanvickyneshwaran]

Stack
Error: Zone already loaded.
at http://localhost:8100/build/vendor.js:126054:15
at http://localhost:8100/build/vendor.js:126668:3
at FUNCTION (http://localhost:8100/build/vendor.js:126031:10)
at Object. (http://localhost:8100/build/vendor.js:126034:2)
at Object. (http://localhost:8100/build/vendor.js:129050:30)
at webpack_require (http://localhost:8100/build/vendor.js:55:30)
at Object.defineProperty.value (http://localhost:8100/build/vendor.js:79337:66)
at webpack_require (http://localhost:8100/build/vendor.js:55:30)
at Object. (http://localhost:8100/build/vendor.js:125549:72)
at webpack_require (http://localhost:8100/build/vendor.js:55:30)

[anoopmv6]

I was facing this problem for last few days..Now I am get out of this "zone already loaded error" from the following way....!

Step 1: Degrade firebase version to lower by typing npm install angularfire2@5.0.0-rc.4

Step 2: run npm install

[mehtaparam]

Ty @rahuljograna @anoopmv6 @guillop solution is working

[GonzaloUNAB2018]

thanks for your answers!! it working!
see ya!

[anoopmv6]

welcome Gonzalo

[arjun526nag]

Uncaught Error: Zone already loaded.
at zone.js:32
at zone.js:644
at FUNCTION (zone.js:9)
at Object. (zone.js:12)
at Object. (zone.js:3060)
at webpack_require (bootstrap 6613f924a1108f55b2e9:54)
at Object.defineProperty.value (vendor.js:69159)
at webpack_require (bootstrap 6613f924a1108f55b2e9:54)
at Object. (vendor.js:117173)
at webpack_require (bootstrap 6613f924a1108f55b2e9:54)

please help us..i try it npm install angularfire2@5.0.0-rc.4 and npm install also but not working

[anoopmv6]

arjun..
after update angularfire run npm install

[arjun526nag]

i am trying this command it's wrkng for me. npm install firebase@4.8.0

[davidenke]

@JiaLiPassion wouldn't it be better to check if zone.js is already initialized? We for example use @angular/elements to create web components. And in some cases they're used inside other Angular applications. So both have to provide zone.js as dependency.

[JiaLiPassion]

@davidenke, sure, this has been fixed here #1093

[davidenke]

@JiaLiPassion but that exposes a flag to allow users to check for themselves if zone.js is loaded, right?

[JiaLiPassion]

@davidenke , I have changed PR title, when the flag is true, the Zone is already loaded error will be thrown, by default, this error will not be thrown.

[amitesh786]

Make sure your not loading the module twice, I had it hiding in my index file:

...
<script src="node_modules/zone.js/dist/zone.js"></script>  // <-- I removed this
...

Incidentally if you load it more than once you screw up the router a bit. You need to click your routing links multiple times when this bug arises after loading it too many times.

I agree, but I just remove some more link related to zone -

I have seen this problem, so I just remove as well as I create system.config.js file that contain info related to link & all script it works perfect.

[robermorales]

@davidenke , I have changed PR title, when the flag is true, the Zone is already loaded error will be thrown, by default, this error will not be thrown.

Which is the intended process to get this fix inside a running angular 6 application? It seems that the fix is in the zone.js master branch but the latest npm release is from 8 months ago.

Thanks,

[JiaLiPassion]

Please wait for a little more longer, the new version will be released soon.

[fishbone1]

This error can also occur if you export symbols at the bottom of polyfills.ts and import them in another ts file of your application.