JavaScript Let vs Var: Practical Code Examples

This collection provides ready-to-use JavaScript code examples that demonstrate the key differences between let and var. Use these snippets to understand how JavaScript let vs var behaves in different scenarios.

Basic Variable Declaration Examples #

Simple Declaration and Assignment #

Undefined vs Uninitialized #

Scope Comparison Examples #

Function Scope vs Block Scope #

Loop Variable Capture #

Redeclaration Examples #

Variable Redeclaration Rules #

Practical Use Cases #

Counter Implementation #

Event Handler Pattern #

Module Pattern with Different Scoping #

Configuration and Settings Examples #

Feature Flags with Different Scoping #

Best Practice Snippets #

Modern Variable Declaration Pattern #

Summary #

These JavaScript let vs var code examples demonstrate:

• Declaration patterns: Basic syntax and initialization differences
• Scope behavior: Function scope vs block scope implementations
• Loop handling: Proper variable capture in asynchronous operations
• Redeclaration rules: When and how variables can be redeclared
• Practical patterns: Real-world usage scenarios and best practices

Use let for modern JavaScript development and only use var when you specifically need function-scoped variables or are working with legacy code.