JAVASCRIPT Tutorial

Variable Declarations

In computer programming, variables are used to store information. A variable declaration defines a variable's name, type, and value.

Steps for Variable Declarations:

  1. Choose a name: The name of the variable should be meaningful and follow naming conventions.
  2. Specify the type: In some languages, you may need to specify the type of data the variable will hold (e.g., integer, string).
  3. Assign a value: You can assign a value to the variable during declaration or later in the program.

Key Concepts:

  • let: Declares a block-scoped variable (available only within its block or curly braces).
  • const: Declares a block-scoped constant (value cannot be changed).
  • var: Declares a function-scoped variable (available throughout the function, even outside of blocks).
  • Scope: The scope of a variable determines where it can be accessed in the program.

Example in JavaScript:

// Use 'let' and 'const' for block-scoped variables
let name = "John";
const age = 30;

// Use 'var' for function-scoped variables
var score = 100;

Best Practices:

  • Use let and const for block-scoped variables whenever possible.
  • Use var only when necessary for function-scoped variables.
  • Avoid using global variables (variables declared outside of any function).