Temporal dead zone in JavaScript

The Temporal Dead Zone (TDZ) is a concept in JavaScript that relates to the hoisting of the variables and the visibility of variables declared with let and const. In the TDZ, a variable exists but it cannot be accessed until it is not declared. This prevents the variable from being used or accessed before a value is assigned to it.

Example: To demonstrate the temporal dead zone of variables defined using let and const.

Javascript

console.log(a);
a=12;
let a;

Output:

Reference error: Can not  access 'a' before its initialization.

To avoid TDZ issues, it’s important to declare variables before trying to access it. It serves as a mechanism to catch potential issues where a variable is accessed before its declaration, promoting cleaner and more predictable code. Understanding TDZ helps to write code that follows the best practices and also reduces the probability of runtime errors in JavaScript.