1 Web Syst. Finals

A collection of vocabulary flashcards covering JavaScript error types, exception handling mechanisms, and debugging features based on the OpenEDG 2023 curriculum.

Syntax

The “grammar" in programming language that is a set of rules that defines the structure of the instructions

Errors

______ in the operation of programs happen due to misconceptions when solving a problem, improper use and
typos of the programming language, or the inability to predict user behavior

keywords

The “Vocabulary" in programming languages which this is a list of words that can be used to build instructions.

Syntax Error

This error violates the language syntax rule, as a declarative sentence should end with a period

Semantic Error

An error where a word is not recognizable in the vocabulary or is used out of context, such as using ‘male’ instead of ‘mall’.

Logical Error

An error that occurs when the code does not produce the originally intended result; it is not easily detectable by a compiler.

SyntaxError

A specific JavaScript error that appears when code is ill-formed, contains typos, or has unmatching parentheses or brackets, preventing execution.

ReferenceError

A type of semantic error in JavaScript , as the compiler does not know its meaning.

• This error occurs when the programmer tries to access a function or a variable that does not exist.

TypeError

This error occurs when a specific value is not of the expected type, such as changing the constant value or checking the length of a variable that is not a string

RangeError

An error generated when a value is passed to a function that is outside of its acceptable range, such as defining an array with a length of $-1$.

Exceptions

When JavaScript detects syntactic or semantic errors, it generates and throws specific objects with information about the encountered error

Exception handling

Also known as error handling, this is the process of preventing a program from stopping when an exception occurs.

finally Statement

this is also an optional block of the try statement, although at least one of them is required or a SyntaxError is thrown.

• It can be used with or without the catch block and is always executed after the try and catch blocks, no matter what errors are thrown.

Debugging

A part of troubleshooting in programming used to identify and fix errors.

debugger statement

A statement that causes the program to stop or halt its execution on the line where it is placed and waits for a decision.

Step-by-Step Program Execution

It is a debugger feature to execute codes on a step-by-step basis.

• It means that program execution can be stopped at any place using the debugger statement and then continue the execution one instruction at a time

Resume

______ the execution of the script typically. The debugger runs the program and “breaks” on user-defined breakpoints

Step Into

treats the function as a set of instructions intended to be executed separately.

• It is used when the code needs to be analyzed in detail.

• The debugger will jump inside the code of the next instruction if it is a function call

Step Over

is used when the next instruction is a call to a function where the impact is unclear or uninterested.

• It treats the function call as something indivisible

Step Out

allows to immediately jump out of a function where the code is paused.

• This action proceeds until the function returns if the debugger is within the code block.