Debugging & Errors

Question 1

What are the steps of debugging?

Answer 1

1. Reproduce the Error
2. Determine the Boundaries of the Error
3. Trace the Code
4. Understand the Problem Well
5. Implement a Fix
6. Test the Fix

Question 2

What is a ReferenceError?

Answer 2

AReferenceErroroccurs when you attempt to use a variable or function that doesn’t exist.

Question 3

What is a TypeError?

Answer 3

1. accessing a property on a value that does not have any properties, such asnullorundefined
2. trying to call something that isn’t a function can also raise aTypeError
3. trying to reassign aconstvariable:

Question 4

What is a SyntaxError?

Answer 4

A SyntaxError occurs when the program does not use proper JS syntax.

Question 5

What is the syntax for a catch statement?

Answer 5

try {
// Do something that might fail here and throw an exception.
} catch (error) {
// This code only runs if something in the try clause throws an exception.
// “error” contains the exception object.
} finally {
// This code always runs even if the above code throws an exception.
}

Question 6

What conditions should be met before you use a catch statement?

Answer 6

• A built-in JavaScript function or method can throw an exception and you need to handle or prevent that exception.
• A simple guard clause is impossible or impractical to prevent the exception.