trackBy is broken in version 9.3

Hello.

I’m using gridster as a dashboard creating tool, so items dynamically change (they can be added or removed on demand). To prevent refreshing item views too many times, I’m using my own trackBy function. Up to 9.2 version everything was working as it should, but now i get the following errors when adding and removing the same item in the same “session” (without reloading page / gridster in between):

vpsc.ts:554 ERROR TypeError: Cannot read property 'gridRenderer' of undefined at GridsterItemComponent.push../node_modules/angular-gridster2/__ivy_ngcc__/fesm5/angular-gridster2.js.GridsterItemComponent.setSize (vpsc.ts:554) at GridsterComponent.push../node_modules/angular-gridster2/__ivy_ngcc__/fesm5/angular-gridster2.js.GridsterComponent.calculateLayout (vpsc.ts:554) at later (vpsc.ts:554) at ZoneDelegate.push../node_modules/zone.js/dist/zone.js.ZoneDelegate.invokeTask (polyfills.js:3504) at Object.onInvokeTask (vpsc.ts:554) at ZoneDelegate.push../node_modules/zone.js/dist/zone.js.ZoneDelegate.invokeTask (polyfills.js:3503) at Zone.push../node_modules/zone.js/dist/zone.js.Zone.runTask (polyfills.js:3271) at push../node_modules/zone.js/dist/zone.js.ZoneTask.invokeTask (polyfills.js:3586) at ZoneTask.invoke (polyfills.js:3575) at timer (polyfills.js:6117)

I tried to change my trackBy function to only track by index and the problem remains.

I saw that some additional trackBy functionalities were added in 9.3. Would it be possible, to add option to disable them on demand?

Thanks.

[tiberiuzuld]

Fixed in v10.1.3 Thank you for reporting the issue and reproducing in stackblits @tmtron and @robleka

[tmtron]

I think I hit the same problem.

IMHO: adding a timeout is not a solution - not even a workaround, because then it may sometimes work and sometimes fail: e.g. when the CPU is busy or on slow mobile devices, etc.

Here is a Stackblitz example to reproduce the issue.

Notes:

• the example uses the default change detection strategy (not OnPush)
• the reset feature uses the workaround as explained in #644

Reproduction steps:

• click on the ID: 0 text to remove the item
• click reset
• click on the ID: 0 again
• check the errors in the console (at the bottom of the stackblitz browser section

It seems that the error occurs in the setSize function as outlined in the comment above.

This maybe be possible if the calculateLayout was deferred and the item was removed while doing that.

In this case, maybe the calculateLayout function can first check if this item has already been destroyed?