Custom angular 7 library with ionic 4 - Can't resolve '../@ionic/angular/dist/core.ngfactory' build prod error

Question

We have built small angular 7/ionic 4 library that we want to use in multiple projects internally by installing through git url. Serving the project works correctly, all imports from library work fine. But when running ng build --prod I get the following error

ERROR in ./node_modules/edetail-core/edetail-core.ngfactory.js 
Module not found: Error: Can't resolve '../@ionic/angular/dist/core.ngfactory' in '/Users/user.name/Documents/ionic/edetails/node_modules/edetail-core'

I've tried different set ups - moving everything to devDependencies (main package.json), adding and removing packages from peerDependencies (library package.json). adding

"lib": {
    "entryFile": "src/public_api.ts",
    "externals": "@ionic/angular"
  }

(lib ng-package.json) but nothing helped. IonicModule gets imported from '@ionic/angular' in the main library module file (edetail-core.module.ts).

Here is ng-package.json

{
  "$schema": "../../node_modules/ng-packagr/ng-package.schema.json",
  "dest": "../../dist/edetail-core",
  "lib": {
    "entryFile": "src/public_api.ts"
  }
}

library package.json

{
  "name": "edetail-core",
  "version": "0.0.1",
  "peerDependencies": {
    "@angular/common": "^7.2.0",
    "@angular/core": "^7.2.0",
    "@ionic-native/core": "^5.0.0-beta",
    "rxjs": "^6.3.3",
    "@ionic/angular": "^4.0.0"
  }
}

main package.json

{
  "name": "edetail-core",
  "version": "0.0.0",
  "scripts": {
    "ng": "ng",
    "start": "ng serve edetail-test",
    "build": "ng build",
    "test": "ng test",
    "lint": "ng lint",
    "e2e": "ng e2e",        
    "npm-pack": "cd dist/edetail-core && npm pack",
    "prepare": "npm run build"
  },
  "private": true,
  "dependencies": {
    "@angular/animations": "~7.2.0",
    "@angular/common": "~7.2.0",
    "@angular/compiler": "~7.2.0",
    "@angular/core": "~7.2.0",
    "@angular/forms": "~7.2.0",
    "@angular/platform-browser": "~7.2.0",
    "@angular/platform-browser-dynamic": "~7.2.0",
    "@angular/router": "~7.2.0",
    "@ionic-native/core": "^5.0.0",
    "@ionic-native/splash-screen": "^5.0.0",
    "@ionic-native/status-bar": "^5.0.0",
    "@ionic/angular": "^4.0.0",
    "@ng-bootstrap/ng-bootstrap": "^4.0.0",
    "bootstrap": "^4.1.3",
    "core-js": "^2.5.4",
    "rxjs": "~6.3.3",
    "scss-bundle": "^2.4.0",
    "tslib": "^1.9.0",
    "zone.js": "~0.8.26"
  },
  "devDependencies": {
    "@angular-devkit/build-angular": "~0.13.0",
    "@angular-devkit/build-ng-packagr": "~0.13.0",
    "@angular/cli": "~7.3.1",
    "@angular/compiler-cli": "~7.2.0",
    "@angular/language-service": "~7.2.0",
    "@ionic/angular-toolkit": "~1.2.0",
    "@types/node": "~8.9.4",
    "@types/jasmine": "~2.8.8",
    "@types/jasminewd2": "~2.0.3",
    "codelyzer": "~4.5.0",
    "jasmine-core": "~2.99.1",
    "jasmine-spec-reporter": "~4.2.1",
    "karma": "~3.1.1",
    "karma-chrome-launcher": "~2.2.0",
    "karma-coverage-istanbul-reporter": "~2.0.1",
    "karma-jasmine": "~1.1.2",
    "karma-jasmine-html-reporter": "^0.2.2",
    "ng-packagr": "^4.2.0",
    "protractor": "~5.4.0",
    "ts-node": "~7.0.0",
    "tsickle": ">=0.34.0",
    "tslib": "^1.9.0",
    "tslint": "~5.11.0",
    "typescript": "~3.2.2"
  },
  "files": [
    "dist"
  ]
}

Any help very much appreciated!

Answer 1

Just add line "@ionic/*": ["node_modules/@ionic/*"] to paths in your tsconfig.json / tsconfig.app.json files

{
    ...
    "compilerOptions": {
        "paths": {
            "@angular/*": ["node_modules/@angular/*"],
            "@ionic/*": ["node_modules/@ionic/*"],
            ...
         }
    }
    ...
}