Angular 4 Circular dependency detected

Question

Upgrading Angular Cli to 1.3.1 I have some warnings now

WARNING in Circular dependency detected: src\\app\\work-sessions\\work-session-list\\work-session-lis         


        

Answer 1

As the warning says, work-session-list.routing.ts depends on index.ts:

import { WorkSessionListComponent } from './index';

And index.ts depends on work-session-list.routing.ts:

export * from './work-session-list.routing';

The first dependency is not necessary, since you could import WorkSessionListComponent directly from its source file:

import { WorkSessionListComponent } from './work-session-list.component';

This change should fix the problem.

Answer 2

Ján Halaša answer is correct. I wanna explain some stuff to make things clear.

index.ts should not be removed, it should still be used.

I had the same problem, in my case I had a cards main modules with many submodules within it. (based on https://medium.com/@tomastrajan/the-best-way-to-architect-your-angular-libraries-87959301d3d3)

so in my tsconfig.ts I had

"@com-tuxin/cards/*": [
 "projects/cards/*",
 "projects/cards"
],
"@com-tuxin/cards": [
 "dist/cards/*",
 "dist/cards"
]

and under projects/cards/src/lib I have a directory for each off my modules, and each one of them has index.ts file.

the reason that I would get a circular dependencies warnings is because I would use barrels includes of a component in the same module that I'm in.

for example I had the sub-module article-card, and I had this code:

import { NgModule } from '@angular/core';
import { CommonModule } from '@angular/common';
import {ArticleCardComponent} from '@com-tuxin/cards/src/lib/article-card;
import {MatCardModule} from '@angular/material/card';
import {MatButtonModule} from '@angular/material/button';


@NgModule({
  declarations: [
    ArticleCardComponent
  ],
  imports: [
    CommonModule,
    MatCardModule,
    MatButtonModule,
  ],
  exports: [
    ArticleCardComponent
  ]
})
export class ArticleCardModule { }

so the problem is with import {ArticleCardComponent} from '@com-tuxin/cards/src/lib/article-card; since I'm in that exact module I should use exact path instead of barrels so I switched it with

import {ArticleCardComponent} from '@com-tuxin/cards/src/lib/article-card/article-card.component';

and that's it, problem is resolved.

and in my case in other libraries where I needed article-card component, I would just need to include @com-tuxin/cards/src/lib/article-card and I would get no circular dependencies.

hope this cleared things up.