JavaScript Reserved Keywords

JavaScript includes a set of reserved keywords that are predefined and cannot be used as variable names, function names, or identifiers. Understanding these keywords is essential for writing correct and error-free JavaScript code.

Key Concepts

• Reserved Keywords: These are words that have special meaning in JavaScript. They are part of the language syntax and cannot be redefined or used for other purposes.
• Purpose: The primary purpose of reserved keywords is to avoid conflicts in the code and to maintain the integrity of the language.

Common Reserved Keywords

Here are some of the most commonly used reserved keywords in JavaScript:

• Control Flow Statements:
  • if
  • else
  • switch
  • case
  • break
  • default
• Loop Statements:
  • for
  • while
  • do
• Functions:
  • function
  • return
• Data Types:
  • var
  • let
  • const
• Object and Class Definitions:
  • class
  • extends
  • super
• Other Important Keywords:
  • this
  • new
  • delete
  • try
  • catch
  • finally

Examples

Using Reserved Keywords

Using a reserved keyword as a variable name will result in a syntax error. For instance:

var if = 10; // This will throw an error

Correct Usage of Reserved Keywords

Reserved keywords must be used in their intended context. Here's how they function:

if (condition) {
    // Code to execute if condition is true
} else {
    // Code to execute if condition is false
}

Conclusion

• Always be cautious not to use reserved keywords as identifiers in your JavaScript code.
• Familiarizing yourself with these keywords will help you avoid common coding mistakes and improve your programming skills.

By understanding these core concepts and examples, beginners can navigate JavaScript more effectively and write cleaner, error-free code.