Solvedangular error TS2451: Cannot redeclare block-scoped variable 'ngDevMode'

I'm submitting a...

[ ] Regression (a behavior that used to work and stopped working in a new release)
[x ] Bug report  
[ ] Feature request
[ ] Documentation issue or request
[ ] Support request => Please do not submit support request here, instead see https://github.com/angular/angular/blob/master/CONTRIBUTING.md#question

Current behavior

node_modules/@angular/core/src/render3/ng_dev_mode.d.ts(9,11): error TS2451: Cannot redeclare block-scoped variable 'ngDevMode'.
node_modules/adv-view-js-comp-core/node_modules/@angular/core/src/render3/ng_dev_mode.d.ts(9,11): error TS2451: Cannot redeclare block-scoped variable 'ngDevMode'.
declare global {
const ngDevMode: boolean;
}
export declare const _ngDevMode: boolean;
export {};

Expected behavior

Minimal reproduction of the problem with instructions

What is the motivation / use case for changing the behavior?

Environment

Angular version: 5.2.1


Browser:
- [ ] Chrome (desktop) version XX
- [ ] Chrome (Android) version XX
- [ ] Chrome (iOS) version XX
- [ ] Firefox version XX
- [ ] Safari (desktop) version XX
- [ ] Safari (iOS) version XX
- [ ] IE version XX
- [ ] Edge version XX
 
For Tooling issues:
- Node version: XX  
- Platform:  Windows

Others:

had to add this line in the main tsconfig

Ran into the same issue today, in my case the problem is one of my libraries that had a direct dependency on @angular/core.
When installing my library in the actual ng-project it also created a node_modules folder there so I had two versions of @angular/core in the project - and both declare ngDevMode in the global scope resulting in the error message described in this issue.

I was actually just running into this very same problem. I created a library with ng-packagr. I then used npm link to include this into a brand new angular/cli project (angular ^5.0.0).

As soon as I included the module from my library, I got this compilation error. The said library is massive, so including that one here wouldn't be feasible. I'll see if I can knock out a bare library and see if it still has same end result. Maybe its angular mismatch, as my library targets angular 4+

I'm having the same problem with 5.2.1.

For me, downgrading to 5.1.3 solved it for now.

npm install @angular/common@5.1.3 @angular/compiler@5.1.3 @angular/compiler-cli@5.1.3 @angular/core@5.1.3 @angular/forms@5.1.3 @angular/http@5.1.3 @angular/platform-browser@5.1.3 @angular/platform-browser-dynamic@5.1.3 @angular/platform-server@5.1.3 @angular/router@5.1.3 @angular/animations@5.1.3 --save

Angular 7, same issue after upgrading from Angular 6 with ng update