Letzz Understand Temporal Dead Zone in JS ( TDZ ) ;)

Let's Understand What is TDZ ;)

What is the Temporal Dead Zone (TDZ)?

• The Temporal Dead Zone refers to a period of time during the execution of your code where variables declared with let and const cannot be accessed before they are actually declared. This period starts from the beginning of the enclosing scope (e.g., a function or a block) and ends when the variable is declared.

Let's understand in easier way.

we have one code below,
Now, What happened - Javascript Code will execute line by line so it runs line number 1 and at line no 1 variable "a" is not declared so it will throw the error of "ReferenceError".

So Now Line No 1 and 2 is called "Temporal Dead Zone"

Now, let's use the same code with "var" variable. so, it'll not throw any error.

Why it's not throwing an error??

• variables declared with var are hoisted to the top of their scope and initialized with undefined. This can lead to subtle bugs, which is why let and const were introduced with the TDZ to avoid such issues.

Now, Let's See How to Avoid it,

How to Avoid Issues with the TDZ

• Declare Variables at the Top: To prevent running into the TDZ, declare your variables at the top of their scope.

• Use const When Possible: If you don't plan to reassign a variable, use const to make your intentions clear and avoid accidental reassignments.

Conclusion

• The Temporal Dead Zone is a concept that ensures variables declared with let and const are not accessed before they are defined. It helps in catching errors early and makes your code more reliable. By understanding and leveraging the TDZ, you can write cleaner and more predictable JavaScript code.

Thanks...