No name was provided for external module

Question

I created a data library, then tried to include the data library into another created library. Built fine, but received - "No name was provided for external module 'my-data' in output.globals – guessing 'myData'". What am I missing?

Complete steps to re-create.

• ng new test-project --create=application=false
• cd test-project
• npm audit fix
• ng g library my-data
• ng g library my-core
• ng g application address-book
• ng build my-data
• Then in my-core.module add import { MyDataModule } from 'my-data';
• Then in my-core.module add imports: [MyDataModule]
• ng build my-core

my-core.module.ts

import { NgModule } from '@angular/core';
import { MyCoreComponent } from './my-core.component';
import { MyDataModule } from 'my-data';

@NgModule({
  declarations: [MyCoreComponent],
  imports: [MyDataModule],
  exports: [MyCoreComponent]
})
export class MyCoreModule { }

• After build get "No name was provided for external module 'my-data' in output.globals – guessing 'myData'"

Answer 1

This is caused because you have an external dependency and you need to declare the name used so that the rollup knows what to look for when building the UMD bundle of my-core.

To fix the warning declare your my-data in ng-package.json

{
  "$schema": "../../node_modules/ng-packagr/ng-package.schema.json",
  "dest": "../../dist/my-core",
  "lib": {
    "entryFile": "src/public-api.ts",
    "umdModuleIds": {
      "my-data": "my-data"
    }
  }
}

I believe this is because since all dependencies are treated as external and your my-data isn't installed through something like npm you need to declare the UMD module id that's expected. See https://github.com/ng-packagr/ng-packagr/blob/master/docs/dependencies.md#resolving-umd-module-identifiers