I activated hot reloading and it's not hot-reloading. When I make a change to any Javascript file, the Packager re-runs and the simulator puts a gray bar at the top saying "Hot reloading..." for a few seconds.
But that is it. The behavior of the app doesn't change and the debugger (in Chrome) shows the unchanged file.
I'm somewhat at a loss. Any idea how I could track this down?
The hot reloading according to the developers is still in development phase and is quite buggy. You could always do a full re-run of the app but the hot reload works like a charm sometimes and not at all otherwise.
https://facebook.github.io/react-native/blog/2016/03/24/introducing-hot-reloading.html
Word of warning: because JavaScript is a very stateful language, hot reloading cannot be perfectly implemented. In practice, we found out that the current setup is working well for a large amount of usual use cases and a full reload is always available in case something gets messed up.
Related
When running my application it is fairly slow to load. So in order to speed up development I am wanting to run my views independently using a testing framework (to avoid needing the whole application load up).
In the process of doing this, I have found that when my views are run from the test runner. I am unable to make changes in XAML and have them reflect in the running application. For example; If I add a textbox to the view via XAML while running, it will not show. I have to restart the test to make it show.
However, when I run my application as a whole. I can edit the XAML and have it make changes to the running app. That is adding a textbox to the view via XAML during running DOES show.
At first I thought it was because the tests were in a different project. So I moved it into the main assembly (everything is in the one assembly/project). The problem is still there. So there must be something else.
One difference, is that I am running my tests from a base class, although I am not sure that should make a difference.
Can anyone tell me how to ensure I can make changes without needing to restart the test?
I am working in an ember application. The version is "ember-cli": "1.13.13".
For a very strange reason, debugger doesn't work in Chrome. (I also tried Safari, and Firefox developer's edition. Same thing.)
Specifically, the problem is I put a debugger statement in a function. Ember app loads and hits the function and the debugger statement in the function. What happens in the Developer Tools -> Sources tab is that it doesn't show me the function that the debugger is in.
Instead it keeps highlighting the last line of app-boot.js file. The breakpoint, or the line that it's paused on, is not showing up at all. (see screenshot attached)
Furthermore when I step into the function call using the down arrow, it remains at app-boot.js, so I have no idea whether it did step into the function or not.
This has been plaguing me for a while now.
I've resolved many times similar error on OSX + Chrome by using Empty Cache and Hard Reload - after that code in Sources tab was updated and I could correctly see actual source code.
Make sure you didn't blackbox scripts of your application.
Alternatively you could try to reinstall npm packages, bower packages - it might be issue with creating source maps in Ember CLI.
If nothing helps please investigate your JavaScript and associated map files and check if something might be missing, or maps don't update. You could possibly try turning them on and off in Ember CLI.
See Source Maps section in Ember CLI guides how to enable/disable them.
I'm currently (trying) to develop an app with Worklight Studio 5.0.6 and Dojo (Mobile) 1.8.3. I have a really hard time to to find a proper method for debugging. After waiting 5-10 minutes for the build an deploy-process on the server, an error usually looks like this in the Chrome debugger:
How am I supposed to track down this error in MY source? The whole stack trace consists entirely of Dojo code which generates an absolutely useless error message after 20 abstraction layers.
Seriously, how do you guys handle this in real life? What methods do you use for debugging Dojo-driven apps in the browser?
spyro
For dojo.parse errors, I find it useful to pause the Chrome debugger on all exceptions (the purple icon on your screenshot, should be blue). You usally get more details about the cause of the error, the name of the DOM node being parsed, etc. in the first exception being raised.
Rémi.
Debugging dojo based application should be the same as debugging any javascript application.
Usually I will follow these steps:
add console.log() somewhere in code: this is fast and most of time this is enough.
set breakpoint in debugger: if step 1 is not enough, you can base on error information to set breakpoint before error line, then step in or step out.
comment out recently changes: for some error which is hard to find the error line, for example, parse error in your case, the good way is comment out your recently changes one by one till back to your last working version. Or, return to your last working version, then add code back one by one.
Create a simple application to reproduce the error : if your application is very complicate and it is hard for you to follow above methods, you can try to create a new application which mimics your current application but with simple logics and try to reproduce the error.
Based on experience : Some errors, for example, extra ',' in the end of array which works at chrome and firefox, will report a nonsense error information at IE. Debug these kinds of errors is very difficult, you can base on your experience or do a google search.
Did you provide isDebug: true in your dojoConfig? Also, try to see if the same occurs in other browsers.
Update: I recently discovered that there are issues with Google Chrome and Dojo debugging and I think it has to do with the asynchronous loading of files. As you can see in the provided screenshot of #spyro, the ReferenceError object is blank (which you can notice because of the empty brackets {}). If you want to solve that, reopen the console of Google Chrome, (for example by tapping F12 twice). After reopening the ReferenceError should not be empty anymore and now you can expand that object by using the arrow next to it and get a more detailed message about what failed.
Usually what I do in situations like that is to place a breakpoint inside the error callback (line 3398 in your case) and then look into the error variable ("e").
I am not sure how familiar you are with the Web Inspector, but once you hit the breakpoint open the Web Inspector 'console' and check for the error properties "e.message" and "e.stack" (just type in "e.message " in the console).
Also, during development it is better to avoid Dojo optimization / minification, which greatly improve your debug-ability.
Bottom line is to try to place the breakpoint before the error is thrown.
I have an app built in node.js and I use the node inspector in order to debug.
But it's quite hard because of this:
My breakpoints are never saved after I restart the server
I cannot put a breakpoint on a file that has not loaded yet; so I have to step into from the first script to the one I want; REALLY PAINFULL!
How do you really debug node.js with node inspector?
The videos on how to use node.js are quite misleading as everything is into a module...
http://www.youtube.com/watch?v=AOnK3NVnxL8
or this one the scripts appear are already loaded in the first script
http://www.youtube.com/watch?v=HJOH0-g8f6E&feature=mfu_in_order&list=UL
Edit:
Nobody can answer this question? :s
In javascript you can set breakpoints using the debugger; statement. However, they will only pause node if a debugger is actually attached.
So launch your node script using
node --debug-brk myfile.js
then launch node-inspector and press the play button to continue to the next breakpoint and it will hit your debugger; breakpoint (at least that works for me ATM)
(as noted in the comments: in recent versions of node you no longer have to separately install node-inspector. If you launch node using node --debug-brk --inspect myfile.js you get a url that launches the debugger in your browser).
you still need one extra click after restarting, but at least your breakpoints are saved.
if your breakpoint is not hit automatically, but only after some user action you don't need the --debug-brk of course.
The problem with client-side breakpoints is that it's hard to keep track of the breakpoint position when the file changes. Unlike in an editor, it cannot keep track of lines being changed, etc.
#RyanOlds suggestion of using debugger; statements is also a good one, but you have to make sure the debugger is connected before the statement is evaluated, because it is ignored otherwise. Starting with --debug-brk is a good way to force this, because the execution is paused on the first line allowing you to attach the debugger and then continue the execution.
You could try debugging with node's internal debugger.
Edit: However, according to the v8 DebuggerProtocol it's possible to set breakpoints on script that hasn't been loaded yet AND you can set breakpoints by function, script and more. It should therefore be possible for node-inspector to keep track of your breakpoints (in a session, or whatever). It doesn't do so right now, though.
Maybe if v8 allows a certain piece of code to trigger a breakpoint, similar to nodes debugger?
Edit: It does, you should be able to trigger a break by throwing any old exception (caught or uncaught).
The new version (0.3.x) of node inspector saves breakpoints in browser's local storage and restores them automatically.
https://github.com/node-inspector/node-inspector/pull/116
Try using IntelliJ WebStorm - there's a free trial and licenses aren't outrageously expensive. It lets you save breakpoints in all your files prior to starting up its own internal node process and remembers them across process restarts.
I agree - node-inspector looks brilliant, but is quite useless unless your app has a clear place to set a breakpoint in the top level script just after your source files have loaded, but before you hit the area you want to debug. You can structure your own code this way, but you won't be so lucky with other helpful libraries you want to include. Also... why should a debugging tool dictate your project structure!
Forgetting breakpoints is extremely unhelpful... most of my debug runs take more than one walkthrough, as in other people's code it's easy to step past where you want to be.
You can use node-codein for inspection. It won't do runtime breakpoints but it should ease the inspection process.
https://github.com/ketamynx/node-codein/
Also worth noting.. vscode has a great debugger for node.
https://code.visualstudio.com/
Available on Mac, Linux, & Windows.
It does runtime breakpoints (without the need of writing debugger; statements),
supports variable watches, and even has a call stack window (very nice).
Everything is so automated, it is now my goto over sublime text when using nodejs (and I LOVE sublime).
This is built in now including saving breakpoints. I just tested it in node 7.3.0.
node --inspect --debug-brk app.js
This prints a url like this
To start debugging, open the following URL in Chrome:
chrome-devtools://devtools/bundled/inspector.html?experiments=true&v8only=true&ws=127.0.0.1:9229/c3d5d93e-9d27-41b9-a4da-607e43c9d4f8
Put that in Chrome and you're good to go.
If you want to skip copy/pasting the url, do this:
npm install -g inspect-process
inspect --debug-brk app.js
Unfortunately the inspect-process method doesn't retain the breakpoints :-(.
Here's a video I made: https://youtu.be/rtZKUnks6jI
I am using a dedicated test SL web application that hosts SL object I am debugging.
I am debugging using basic F5 and use browser Google Chrome. Sometimes a bug happens, how I reproduce it.
I was running build->debug like 100 times already, but then I made a mistake that caused StackOverflowException and happened in main page constructor and afterwards when I rebuild and hit F5 it says no symbols have been loaded. Note that NOTHING has changed , I use the same 2 buttons combinations rebuild solution-> start debugging.
In order for debug to continue to attach I need to close XAML main page , open it again (in visual stuido) and hit rebuild ->f5 again, afterwards it works fine. (found this solution after SOME time)
I am not sure whats bugged but it appears to be a bug somewhere in SL to me.
Question is - whats going on maybe someone can explain.
This sounds more like Chrome's isolation mode for plug-ins. Generally speaking it's best to manually attach to the Chrome process that is running Silverlight (which isn't always one VS attaches to when pressing F5).
Actually error was super simple, I wasn't understanding how "exactly" xap works, it was a little more magical to me than it is. I just needed to rebuild & clear cache in browser ( chrome in this case) to attach successfully. For some reason I thought that local version doesn't require clear cache call.
Actually chrome is pretty bad to debug silverlight so I recommend IE for this sole purpose, sometimes debugger simply fails to attach to chrome, in that case you usually need to do this by attach to process - choose chrome with silverlight name there.