Angular 6 [WDS] Disconnected Error on Firefox

Question

I use Angular and i get console error only on Firefox "[WDS] Disconnected!".

Here is my Angular-Cli version.

Angular CLI: 6.0.1
Node: 8.11.1
OS: win32 x64
Angular: 6.0.1
... cli, common, compiler, compiler-cli, core, forms, http
... language-service, platform-browser, platform-browser-dynamic
... router

Package                           Version
-----------------------------------------------------------
@angular-devkit/architect         0.6.1
@angular-devkit/build-angular     0.6.1
@angular-devkit/build-optimizer   0.6.1
@angular-devkit/core              0.6.1
@angular-devkit/schematics        0.6.1
@angular/animations               6.0.4
@ngtools/webpack                  6.0.1
@schematics/angular               0.6.1
@schematics/update                0.6.1
rxjs                              6.2.0
typescript                        2.7.2
webpack                           4.6.0

Answer 1

Solved it today by running npm update. Apparently it was a bug with an older version of Webpack.

Answer 2

This error appeared again for me under angular 7.2.1.

The solution was to add the following line in angular.json under architect>serve>options:

"disableHostCheck": true