JS: Error Handling & Debugging

Debugging is a process of testing and finding errors and reducing their occurrence in the future.

>> This requires that you understand the context of the implementation of your program to discover errors in it

The console is a great helper in minimizing the area where the error is, so that you can try to find the exact error.

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JavaScript contains *7 different types of errors. Each creates its own error object, which can tell you its line number and provide a description of the error.*

1. RangeError:

   This is thrown when a number is outside an allowable range of values.

2. ReferenceError:

   This error is thrown when a reference made to a variable/item is broken. That is the variable/item doesn’t exist.

3. SyntaxError:

   This is the most common error we encounter. This error occurs when we type code that the JS engine can understand.

4. TypeError:

   TypeError is used to indicate an unsuccessful operation when none of the other NativeError objects are an appropriate indication of the failure cause.

5. URIError:

   This indicates that one of the global URI handling functions was used in a way that is incompatible with its definition.

6. EvalError:

   This is used to identify errors when using the global eval() function.

7. InternalError:

   This error occurs internally in the JS engine, especially when it has too much data to handle and the stack grows way over its critical limit.

>> If you know you might get an error, you can safely handle it with try, catch, and finally statements. Use it to provide users with helpful feedback.