- [ ] new
- [ ] build
- [x] serve
- [ ] test
- [ ] e2e
- [ ] generate
- [ ] add
- [ ] update
- [ ] lint
- [ ] xi18n
- [ ] run
- [ ] config
- [ ] help
- [ ] version
- [ ] doc

ng new testsourcemap
cd testsourcemap

{
  "compileOnSave": false,
  "compilerOptions": {
    "baseUrl": "./",
    "outDir": "./dist/out-tsc",
    "sourceMap": true,
    "declaration": false,
    "downlevelIteration": true,
    "experimentalDecorators": true,
    "module": "esnext",
    "moduleResolution": "node",
    "importHelpers": true,
    "target": "es2015",
    "typeRoots": [
      "node_modules/@types"
    ],
    "lib": [
      "es2018",
      "dom"
    ],
    "allowJs": true,
  },
  "angularCompilerOptions": {
    "fullTemplateTypeCheck": true,
    "strictInjectionParameters": true
  }
}

function add(a,b){
  return a+b;
}

export {
  add
};

import { Component } from '@angular/core';
import * as test from './testjs';

@Component({
  selector: 'app-root',
  templateUrl: './app.component.html',
  styleUrls: ['./app.component.css']
})
export class AppComponent {
  title = 'testsourcemap';
  
  constructor() {
    let add = test.add;
  }
}

import * as tslib_1 from "tslib";
function add(a, b) {
    return a + b;
}
export { add };
//# sourceMappingURL=testjs.js.map

Angular CLI: 8.3.8
Node: 10.15.3
OS: win32 x64
Angular: 8.2.10
... animations, common, compiler, compiler-cli, core, forms
... language-service, platform-browser, platform-browser-dynamic
... router

Package                           Version
-----------------------------------------------------------
@angular-devkit/architect         0.803.8
@angular-devkit/build-angular     0.803.8
@angular-devkit/build-optimizer   0.803.8
@angular-devkit/build-webpack     0.803.8
@angular-devkit/core              8.3.8
@angular-devkit/schematics        8.3.8
@angular/cli                      8.3.8
@ngtools/webpack                  8.3.8
@schematics/angular               8.3.8
@schematics/update                0.803.8
rxjs                              6.4.0
typescript                        3.5.3
webpack                           4.39.2