One library can't import another library

[lsa-shanghai]

Versions

Angular CLI: 6.0.0
Node: 10.0.0
OS: darwin x64
Angular: 6.0.0
... animations, cli, common, compiler, compiler-cli, core, forms
... http, language-service, platform-browser
... platform-browser-dynamic, router

Package                            Version
------------------------------------------------------------
@angular-devkit/architect          0.6.0
@angular-devkit/build-angular      0.6.0
@angular-devkit/build-ng-packagr   0.6.0
@angular-devkit/build-optimizer    0.6.0
@angular-devkit/core               0.6.0
@angular-devkit/schematics         0.6.0
@ngtools/json-schema               1.1.0
@ngtools/webpack                   6.0.0
@schematics/angular                0.6.0
@schematics/update                 0.6.0
ng-packagr                         3.0.0-rc.2
rxjs                               6.1.0
typescript                         2.7.2
webpack                            4.6.0

Repro steps

• Step 1
  ng generate library model-lib
  ng generate library ui-lib
  ng generate application portal
• Step 2
  ng build model-lib
• Step 3
  import { ModelLibModule } from 'model-lib' in portal module
  ng build portal
• Step 4
  import { ModelLibModule } from 'model-lib' in ui-lib module
  ng build ui-lib

Observed behavior

BUILD ERROR
projects/ui-lib/src/lib/ui-lib.module.ts(3,29): error TS2307: Cannot find module 'model-lib'.

Desired behavior

Library should import other library same as application.

[hwangzhiming]

Have same issue, even added two libs to tsconfig.json file

[Etchelon]

Same, it's a pretty critical issue imho. I tried playing with the compiler options "baseUrl" and "path", but the error is always the same during the compilation step with ngc.
Note that the IDE's (VS Code) intellisense works in resolving an import from library 1 written inside a file of library 2, but then the compilation of library 2 fails.

[aitboudad]

solved that issue by defining libs in paths see https://github.com/formly-js/ngx-formly/blob/master/tsconfig.json#L20-L22 and for building libs I used a patch in ng-packgr to make it work

[Etchelon]

@aitboudad can you point me to a link explaining how ngpackagr patches work? I can't find it in their documentation. I mean, does the .patch file just need to be in the project folder somewhere and have to be named ng-packagr.patch?
It could solve my issue because I've already mapped the dependency library correctly in paths but to no avail.

[aitboudad]

@Etchelon it's just a temporary fix :) https://github.com/formly-js/ngx-formly/blob/master/package.json#L13

[Etchelon]

Thanks @aitboudad.
While trying to figure out what the hell that patch is (looks like a piece of git diff, something I'm not confortable with), I manually added a log inside the ng-packagr script for ngc compilation, and I've realized two things:

1. library 2, which doesn't compile because tsc (or ngc? Didn't dig too much) cannot resolve absolute paths from library1 pointing to dist/library1, inherits the main tsconfig.json, where the following options are specified:
   { "baseUrl": "./", [...], "paths": { "library1": ["dist/library1"], "library2": ["dist/library2"] } }.
   My library2's tsconfig.lib.json was trying to override these options like this:
   { "baseUrl": "../../" }
   When I added the following log lines:
   
   I noticed that baseUrl would still point to "./" (which, for the compilation of library 2, would be {root}/projects/library2/src and therefore this baseUrl was not overridden!
   Moreover, I would expect the path to be {root}/projects/library2, where tsconfig.lib.json is, not the {root}/projects/library2/src folder, which is 1 level deeper!
   So my solution is to override the paths option inside library2's tsconfig, using 3 times the "../" command:
   { [...], "paths": { "library1": ["../../../dist/library1"] } }
   and now it works.

[aitboudad]

@Etchelon another easy way is to add paths in tsconfig.lib.json but it'll not wok when using a secondary entry points

same here

[clydin]

With a library generated with 6.0.2+ this should no longer be an issue. Support for secondary entry points will be corrected via angular/devkit#933

For an existing library exhibiting the issue, ensure the library that contains the import has its own tsconfig and that it has a paths section as described in the previous responses.