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"All about Variables"


 "In the realm of JavaScript's code,
Variables hold a powerful mode."


In JavaScript, variables are used to store data values. 

Variable Declaration:

In JavaScript, you can declare variables using the var, let, or const keywords.
Already discussed in the previous blog ( Link to it ).







1. Variable Naming:

  • Variables can have a wide range of names, but they must follow certain rules:
  • They can contain letters, digits, underscores, or the dollar sign.
  • The first character must be a letter, an underscore, or a dollar sign.
  • Variables are case-sensitive (myVariable and myvariable are considered different variables).
  • It's a good practice to use descriptive names that reflect the purpose of the variable.
JavaScript has a set of reserved keywords that have predefined meanings and cannot be used as identifiers (such as variable names or function names) in your code.




2. Variable Assignment:

  • You can assign a value to a variable using the assignment operator (=).
  • The assigned value can be a number, string, boolean, array, object, or any other valid JavaScript data type.

3. Variable Reassignment:

  • Once a variable is declared, you can update its value by assigning a new value to it.
  • Variables declared with let can be reassigned with a new value, while variables declared with const are read-only and cannot be reassigned.

4. Variable Scope:

  • The scope of a variable determines where it is accessible within your code.
  • Variables declared with var have function-level scope, meaning they are accessible within the function in which they are declared or globally if declared outside of any function.
  • Variables declared with let and const have block-level scope, meaning they are accessible only within the block of code they are declared in (e.g., inside a loop or an if statement).

Supplementary Reading:


In JavaScript, variables are stored in memory during the execution of a program. The memory location where a variable's value is stored depends on the type of variable and its scope. Let's discuss how variables are stored in memory in JavaScript:

Primitive Data Types:

Variables that hold primitive data types (such as numbers, strings, booleans, null, and undefined) store the actual value directly in memory.

When you declare a variable and assign a primitive value to it, the value is stored in memory at the variable's memory location.




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