AOT: Encountered undefined provider! Error: The Angular AoT build failed.

[huan]

When this module is imported by @chatie/app, npm run ionic:build --aot said Encountered undefined provider!.

After diving into the code, the issue Chatie/app#33 is caused by this module @chatie/db.

Even an empty empty import could be able to cause the error message:

Encountered undefined provider! Error: The Angular AoT build failed. Usually this means you have a circular dependencies (might be caused by using 'barrel' index.ts files.

import {} from '@chatie/db'

Wired.

See Also

• Angular Glossary: Barrel
• AOT + barrels not supported angular/angular#13193
• https://stackoverflow.com/questions/49713890/angular-lazy-loaded-module-dependencies-encountered-undefined-provider

[huan]

UPDATE

I found this issue caused by using 'barrel' index.ts files, just as the error message said.

However, it's very strange that it's just a very simple barrel index.ts, there are no circle dependencies at all.

db/src/db.module.ts

Lines 9 to 15 in de17acc

	import { Db } from './db'
	import { BotieStore } from './botie/'
	import {
	GraphCoolIdToken,
	} from './config'
	import { GiftieStore } from './giftie'
	import { HostieStore } from './hostie'

If I change the above code to

- import { BotieStore }   from './botie/'
+ import { BotieStore }   from './botie/botie-store'
- import { GiftieStore }  from './giftie'
+ import { GiftieStore }  from './giftie/giftie-store'
- import { HostieStore }  from './hostie'
+ import { HostieStore }  from './hostie/hostie-store'

Then it will work with AOT in @chatie/app.

Wired.