TypeScript Variables Explained

In the world of TypeScript, variables play a crucial role in storing and manipulating data throughout your code. Here's a breakdown of how variables work in TypeScript, focusing on their scope, declaration, and type annotations.

TypeScript offers three main ways to declare variables: , , and . Each type of variable declaration has different behavior when it comes to reassigning values and scoping.

For instance, provides block-level scope, meaning it's only available inside the function or block where it's declared. For example, is a local variable, accessible only within the function. On the other hand, is used for variables that should not be reassigned after their initial value. Attempting to reassign a variable results in a compile-time error in TypeScript.

Variables declared outside any function or block are accessible throughout the entire program (Global Scope). is an example of a global variable, while is a private class-level variable, accessible only within the class.

In TypeScript, variables declared within a function or block are accessible only within that function or block (Local Scope). Trying to access outside the function results in an error because it's out of scope.

Type annotations in TypeScript allow explicit definition of variable types, improving code clarity and reducing errors. For instance, the function uses type annotations for both parameters and return type to ensure type safety. The variable must hold a string value, while the variable must hold a number value.

It's worth noting that using in TypeScript can lead to unexpected behavior due to hoisting. Instead, it's recommended to use or for variable declarations.

Moreover, variable names in TypeScript can contain alphabets both Upper-case as well as Lower-case, digits, and special characters and . However, variable names cannot start with a digit and we cannot use any other special characters apart from and in variable names.

The class has a property set to 50000 and a method that prints the salary. Additionally, the variable must be a boolean.

Lastly, it's interesting to understand how variables change when a component is used within another component, as it manages state changes and variable reactivity within components, such as the useState function in TypeScript (commonly used in React). However, this topic is beyond the scope of this article.