How do you debug JavaScript issues when loading dynamic content?

Consider asynchronous behavior and event-driven bugs. Utilize `async/await` for clarity, and check for promise rejections. Inspect element states before and after dynamic loads, and monitor event listeners for unexpected triggers.

Utilize Chrome Developer Tools (DevTools) for effective JavaScript debugging. Access DevTools by right-clicking and selecting 'Inspect' or using Ctrl+Shift+I. Check the 'Console' tab for JavaScript errors and stack traces. Use the 'Network' tab to monitor network requests and troubleshoot dynamically loaded content.

Step 1: Browser developer tools Step 2: Code functionality Step 3: AJAX requests Step 4: Conflicts Step 5: Console.log() Step 6: Cross-browser compatibility Step 7: Systematic debugging Step 8: Use alert('hello')

When debugging JavaScript issues with dynamic content, use browser developer tools to inspect the DOM, check network requests for loading errors, and utilize console logging to track variables and function calls.

Set breakpoints in your JavaScript code using the "Sources" panel in dev tools. This allows you to pause the execution of your code at specific points and inspect the state of variables, the call stack, and other runtime information.

Breakpoints, a crucial DevTools feature, halt code execution at specific lines. In DevTools' 'Sources' tab, open the relevant JavaScript file and click the line number to set a breakpoint. When triggered, it pauses code execution, allowing variable inspection and step-by-step code analysis.

With breakpoints, we are able to see our code running even line by line, so that we can keep track of what's going on. This is very useful, for example, when we have some issue with values not being correct, we can, through use of breakpoints, check the values at specific moments and keep up with them.

Using Breakpoints in javascript code is very useful, In my experience, I use them in two cases when I know where approximately are the bug and if the code is small. When the code is long I usually make points of recognition using logs in the console. It allows discover if a function is working or not. In case the logs didn't help, I use breakpoints in each function to analyze small segments of code. Everything depends on how hard is a bug to find.

It's not just breakpoints, there's conditional breakpoint, log break points, step over, step in and so much more that allow us to see the flow in the application at a very low level. Truly, the debugger is one of the best tools made for debuggin!

To gain insights into JavaScript execution, utilize the 'Performance' tab in DevTools. Start recording before triggering dynamic content and stop after it loads. Analyze the timeline to spot bottlenecks and understand function calls for optimizing performance.

Flame Graph help you to understand exactly which function is being the bottleneck, analyse optimisation and debug issues. You can zoom in, zoom out to go more detailed or less

Very useful when profiling recursive call stacks processing data structures like [de|en]coding. Add it to your CI/CD pipeline.

To monitor variables during code execution, utilize 'Watch Expressions' in DevTools. Add expressions in the 'Watch' tab of the 'Sources' panel to track specific variables. As you debug with breakpoints, watch expressions update in real-time, aiding in pinpointing state-related issues.

Watch Expressions let you at a glance see what exactly is happening to the data, any issues that you can find can be quickly looked upon at a glance.

A nice way to hook and track the state machine as you step through your application. Make use of it to help identify functionality that the debugger may have skipped over due to any lacking support in the IDE stack.

Logging data into seperate sinks allow us to filter data and see according to different sources. You can see errors, warnings and all other stuffs properly

Take advantage of the console beyond error logging. Employ console commands like console.log(), console.warn(), and console.error() to output variables, execution flow, and custom debugging messages. When troubleshooting dynamic content, logging data just before rendering offers insights into data fetching and processing.

Event Listeners: If you're using event listeners to trigger the loading of dynamic content, make sure that they are being properly attached and triggered. Use console.log() statements inside your event listener functions to check if they are being called correctly.

By strategically placing console.log statements throughout javascript code, we can track the flow of data, identify errors, and understand how variables change over time. This real-time feedback helps us pinpoint issues more quickly and efficiently than simply relying on error messages or breakpoints in a debugger.

The console helps a lot using it with breakpoints to understand the context of the bug and with that, you can change what the code needs. Using the logs in critical or specific situations could be helpful, but we need to use the logs wisely because if you always print logs the code/application becomes slow, using the logs to show specific and important information like errors, warnings, or connection success, will make a console clean and useful.

Network Throttling in the 'Network' tab of DevTools enables simulation of various network conditions. Mimicking slow speeds helps observe how JavaScript handles latency, ensuring dynamic content behaves gracefully under adverse conditions.

Inspect Network Traffic: Use the network tab in your browser's developer tools to inspect the network requests made by your page. Make sure that the dynamic content is being loaded correctly and that there are no errors in the requests or responses.

When we are creating a new application we are usually in a good network with good speed and ping, but the user commonly uses a phone network or a very slow network connection, and to give the users a good experience we must start using the network throttling,. Google DevTools has the configuration in Network and you can switch your network connection from Full speed to 3G, Slow 3G, or another very custom. I recommend a lot of start using that kind of tools to help users enjoy our creations.

Network tab is usefull to know the response of an AJAX load, with fetch() or httprequest(), because we can see the statut and the response directy in. I've see a new feature of dev tools in firefox : Firefox Profiler. Very powerfull, with many feature difficult to understand. It may like be as Google Lighthouse... Anybody has informations about it ?

I would consider modern observability approach including dynamic instrumentation for live debugging using tools like Lightrun and similar. Such tools allows inspection of issues at runtime and without stopping the app from running hence allowing better flexibility in debugging and faster resolution of the issues

Besides the basic debugging, there are a lot of third-party tools that you can try as well. Probably you will be using some framework, so you can choose some specific tech that fits best, like React Dev Tools/Redux Dev Tools for React and Flipper for React Native for example. That way you can check more scenarios, see a bigger picture and make better decisions.

Feel free to explore different debugging techniques and experiment with various DevTools features to find what works best for your specific scenarios. Additionally, don't hesitate to seek advice from peers or online communities when facing particularly challenging dynamic content issues. Remember, debugging is often an iterative process, so stay patient and persistent until you uncover and resolve the underlying issues.

I think that at this point if your javascript promise load some API, you need to consider the state of reponse in the Network tab. Inside you can see header, request and response and check if it was correctly implemented. A tools like Postman will be usefull at this point if Network traffic tab is too light