Adding breakpoint to events that are raised during the "loading" of a Page are not hit the first time that Page is navigated to

[VladimirAmiorkov]

Environment

• CLI: 5.2.4
• Cross-platform modules: 5.3.0
• Android Runtime: 5.2.0
• iOS Runtime:5.2.0
• Plugin(s):
• VSCode: 1.32.3 (1.32.3)

Describe the bug
When I place a breakpoint in an event that is consider to be raised very quickly like the onLoaded event of a Page, that breakpoint is not hit if this is the first navigation to that Page in the app's lifecycle. After that if you go back to the previous Page and navigate again to the other one the breakpoint is hit correctly.

To Reproduce
Using the nativescript-ui-listview demo application that can be found here simply add a breakpoint here, start the app and navigate to the "Getting Started" example.

Expected behavior
Breakpoints are hit correctly no matter where they are placed in the app's code.

Sample project
Using the nativescript-ui-listview demo application that can be found [here]

[VladimirAmiorkov]

Workaround is to manually set the debugger in the code:
debugger;

[DimitarTachev]

Hi @VladimirAmiorkov

Thanks for the detailed description.

This issue should be reproducible only on very slow devices.

When a script file is loaded for the first time, it has to be parsed and the Runtime sends a script parsed message through the Chrome protocol. Once this message is received, the client (Chrome Dev Tools or Visual Studio Code) sets the specified breakpoints. If the app is running on a slow device, the script parsing is slower than the page load and the breakpoint is skipped on the first navigation.

In order to get the breakpoints during page navigation working, you could use hardcoded debugger; statements in your code, run on a faster device or run your app with --bundle which will bundle all of your pages in bundle.js and they will be parsed together during the app start.