fix: The view didn't update after changes an observable variable

[HcySunYang]

🐛 Bug Report

I was following the code snippets that the documentation has given:

💻 Repro or Code Sample

Looking at the below gif, if you can't see the gif clearly, you can click on it and open it in a new tab so that you can see it more clearly:

Whenever I add a new friend, the name variable will be set to an empty string, but the view no longer updated.

🤔 Expected Behavior

The input should be cleaned up

😯 Current Behavior

The name variable has been set to an empty string, but the input has not been cleaned up.

💁 Possible Solution

No idea

🔦 Context

Just run the code snippets provided by the documentation, just like the first screenshot I gave

🌍 Your Environment

Window

[HcySunYang]

The root cause is that I am not using the ts-loader...