JavaScript Errors
8 lessonsAbout 48 minutesAdvanced
This part of the JavaScript Tutorial runs from JavaScript Errors through to JavaScript Debugging. There are 8 lessons here, and working through them takes about 48 minutes at a steady pace.
It follows on from JavaScript Numbers & Math, so finish that first if you have not already — the examples below assume you are comfortable with it.
Each lesson below says what it covers before you open it. Read them in order the first time; afterwards this page works as a index you can jump back into when you need to check one thing.
- 1JavaScript ErrorsAn error stops the current code and travels up until something handles it.
- 2JavaScript try catchtry runs code that might fail, and catch handles it when it does.
- 3JavaScript throwthrow raises an error deliberately when something is wrong.
- 4JavaScript finallyfinally runs whether the code succeeded or failed.
- 5JavaScript Error TypesJavaScript has several built-in error types, each describing a different kind of failure.
- 6JavaScript Custom ErrorsA custom error class describes a failure specific to your own program.
- 7JavaScript Error Handling PatternsGood error handling is about deciding where a failure should be dealt with.
- 8JavaScript DebuggingDebugging is the process of finding out why code does not do what you expected.