export 'default' (imported as 'core_1') was not found in '@angular/core'

Type of Issue

[x] Bug Report
[ ] Feature Request

Versions

ng-packagr: v1.5.0-rc.1
node: v6.11.0
@angular: v4.4.6
rxjs: 5.5.0
zone.js: 0.8.18

Description

When packaging my library i get the following warning:

'default' is not exported by 'node_modules\redux\es\index.js'
'default' is imported from external module 'rxjs/add/operator/let' but never used
'default' is imported from external module 'rxjs/add/operator/distinctUntilChanged' but n
'default' is imported from external module 'rxjs/add/operator/map' but never used
'default' is imported from external module 'rxjs/add/operator/filter' but never used
'default' is imported from external module 'rxjs/add/operator/switchMap' but never used

and when using my library in an application, i get the following warnings:

"export 'default' (imported as 'core_1') was not found in '@angular/core'

Here’s my setup: ng-package.json

{
  "$schema": "./node_modules/ng-packagr/ng-package.schema.json",
  "src": "lib",
  "dest": "dist/lib",
  "workingDirectory": ".ng_build",
  "lib": {
    "entryFile": "public_api.ts",
    "externals": {
      "oidc-client": "./node_modules/oidc-client/dist/oidc-client.min.js",
      "rxjs/add/operator/let": "Rx.Observable.prototype"
    }
  }
}

public_api.ts_

export * from './my-lib/my-lib.module'

tsconfig:

{
  "compileOnSave": false,
  "compilerOptions": {
    "outDir": "./dist/src",
    "baseUrl": "src",
    "paths": {
      "my-lib": [
        "dist/lib"
      ]
    },
    "sourceMap": true,
    "declaration": false,
    "moduleResolution": "node",
    "emitDecoratorMetadata": true,
    "experimentalDecorators": true,
    "target": "es5",
    "typeRoots": [
      "node_modules/@types"
    ],
    "lib": [
      "es2017",
      "dom"
    ]
  }
}

I haven’t been able to reproduce the issue in an example app and I cannot make any sense of this but I hope you might. Thanks

[avatsaev]

I think it’s due to some third party libraries not respecting the Angular Library Format, so the imports you use from the lib, screws with the angular compiler (or webpack).

Here a solution I’ve found to debug, find out which lib breaks the transpilation, and fix the problem.

Suppose I have my-lib project that compiles with ng-packagr into dist/lib folder

After compilation in dist/lib/my-lib.js there is a problem with imports (core is not imported correctly):

• Fist step is to figure out which lib is breaking everything so just control+F and look where core is used:

So one of the imports from TimeAgoPipe library is breaking the compilation

• Project wide search (ctrl+shif+f ‘time-ago-pipe’) I only import from time-ago-pipe lib once:

So the solution in this case is to add the entire import path into externals in ng-package.json (if you have other imports from this lib add them too):

After which everything compiles fine:

The most confusing part of this bug is not knowing where the error comes from, because the ng-packagr packages the lib just fine, without warnings or spitting out an error.

[markus-wa]

For me this happened because I didn’t have my compilerOptions.module set in tsconfig.json, which resulted in commonjs being used as default (for targets es3 or es5).

Setting it to es6 fixed it for me.

Relevant part:

{
  "compilerOptions": {
    "module": "es6"
  }
}