Tips for Debugging JavaScript Under the JavaScriptCore Framework

Some features in native app development are well-suited for a Hybrid approach. I have long wanted to try , but since neither the front-end nor the Android team was on board, the iOS side could only use JavaScriptCore to inject a object and enable JS to call Objective-C methods. While the implementation itself is not particularly difficult, debugging issues when they arise can be a real headache. I recently looked into JS debugging techniques and summarized them in the context of my project. JS debugging methods: - The most obvious one is . - Then there is . However, it cannot be used in a client-side WebView. In that case, you can use a small trick: when defining the JS interface, add an extra method: Then implement it in the file: And in the corresponding JS file: This replaces with , so console output will now appear in Xcode's console. - You can also use to check the type of a value. Possible types are , , , , , and . - When appropriate, you can call a JS method from Objective-C code using: . Be mindful of the conversion between and Objective-C objects when printing.