after running the app, got this issue

[ikhsanhabibi]

I can not also add product by submitting the save button, please fix it.

[ikhsanhabibi]

[saqibRafique]

@ikhsanhabibi Same issue found on my side.

[commentatorboy]

The problem is that there are no server called localhost:3000 (I think).
The thing is that you have not created a server that handles the request.
The service is only for calling api and fetching from the api.
So I do not understand why this is a "crud" example when there is no clear way to "RUD".
You need a backend, like this (or use f.x. laravel or .NET), to create a backend:
https://github.com/didinj/NodeRestApi/blob/master/routes/products.js