Uncaught TypeError: Property '__zone_symbol__then' of object [object Promise] is not a function

[rudgal]

Observed this on Mobile Chrome/33.0.1750.170 using zone.js 0.8.26:

Although that's a pretty outdated browser, I'm still reporting it just in case the issue occurs with other userAgents too.

I tracked the problem down to the following code snippet that patches the then-method of Promise

 function patchThen(Ctor: Function) {
 const proto = Ctor.prototype;

 const prop = ObjectGetOwnPropertyDescriptor(proto, 'then');
 if (prop && (prop.writable === false || !prop.configurable)) {
 // check Ctor.prototype.then propertyDescriptor is writable or not
 // in meteor env, writable is false, we should ignore such case
 return;
 }

 const originalThen = proto.then;
 // Keep a reference to the original method.
 proto[symbolThen] = originalThen;
.
.
.

In case of chrome 33 then is initially not configurable, hence patchThen returns before the original method is patched.

Compared to current chrome:

Imho the reference to originalThen should be kept, even if the properties indicate that it is not writable or not configurable. This was the case prior to the changes with #1041 .

[JiaLiPassion]

@rudgal , thank you for posting the issue, this is a bug, I will fix this one.

[benrobster]

Is there a workaround in the mean time?

(This is challenging because Chromium 33 is the fixed (non-upgradeable) version of WebView on Android 4.4.3 & 4.4.4 which still has quite a bit of distribution.

[TheCraccer]

We're still having this issue, too. Any solution for this?

[rudgal]

In our case reverting back to version 0.8.20 worked as temporary solution.

[JiaLiPassion]

@benrobster , @TheCraccer , @rudgal
you can try to add following code after import zone.js in polyfills.ts.

import `zone.js/dist/zone`; // imported by Angular CLI

(Promise.prototype as any)['__zone_symbol__then'] = Promise.prototype.then;

[TheCraccer]

@JiaLiPassion that seems to work. Thanks a lot!
Edit: The workaround did not work. Still crashing on chrome :( @rudgal reverting back to 0.8.20 worked as temporary for us too

[johnny-mh]

@benrobster @TheCraccer Add patching code before import syntax. in my case that works.

@JiaLiPassion I think your code just trick. so we need to find safe way to solving this problem.

[JiaLiPassion]

@everedifice , to be more safer, you can update the code like this.

import `zone.js/dist/zone`; // imported by Angular CLI
if (!(Promise.prototype as any)['__zone_symbol__then']) {
 (Promise.prototype as any)['__zone_symbol__then'] = Promise.prototype.then;
}

[asher-fire]

@JiaLiPassion This method is invalid

[asher-fire]

I am using android 4.4.4

[JiaLiPassion]

@zds-jack , you can try the walk around here, and this has been fixed, but need to wait for the next release.

import `zone.js/dist/zone`; // imported by Angular CLI

(Promise.prototype as any)['__zone_symbol__then'] = Promise.prototype.then;

[asher-fire]

@JiaLiPassion I created a new project and used this method, but I still get this error

[johnny-mh]

@zds-jack Are you tried that add polyfill code before import 'zone.js/dist/zone' syntax?

[JiaLiPassion]

@zds-jack , it is a little weird , could you debug in Chrome dev tools console and check
what properties exist in Promise.prototype ?