How to save add and save item to angular file?

Question

I’m trying to use this example:

But I’m not getting that record. That is, I enter data is saved, but when I update the page undoes the changes, and in the file does not add new items.

All the examples I have tested happen the same. I judge for lack something that allows you to save data in the file, but I don’t know what it is?

I don’t know much about Angular.