PG2

Testing and Debugging PhoneGap Applications
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function onDeviceReady() {
//Just writing some console messages
console.warn("This is a warning message!");
console.log("This is a log message!");
console.error("And this is an error message!");
}
Debug Example
Look at the console to see the messages the application
has outputted
As you can see from the code, all the application has to do is call the appropriate
method and pass in the text of the message that is supposed to be written to the
console.
In some cases, the browser component executing your application’s web content
won’t throw an error if you try to do something that’s not supported in your Java-
Script code (calling a PhoneGap API function that doesn’t exist, for example,
because you’ve misspelled it). In this scenario, simply wrap the errant call in a
try/catch block so your application will have a chance to write its error to the
console, as shown in the following example:
try {
console.log("Validating the meaning of life");
somefunctioncall("42");
} catch (e) {
console.error("Hmmm, not sure why this happened here: " +
e.message);
}
Figure 2-6 shows the messages from Example 2-1 highlighted in the Xcode console
window. This window is accessible while the program is running on an iOS
simulator, so you can debug applications in real time.
Figure 2-6 ​ ​Viewing console messages in Xcode