Difference between let var and const | JavaScript Tutorials in Hindi | Interview Question #9

In JavaScript, there are three types of variable declarations: let, var, and const. The main difference between them is their scope and mutability. ‘let’ and ‘var’ are used to declare variables that can be reassigned later, whereas ‘const’ is used to declare variables that cannot be reassigned. The ‘let’ keyword has block scope, meaning that a variable declared with ‘let’ is only accessible within the block it is defined in. The ‘var’ keyword has function scope, which means that a variable declared with ‘var’ is accessible throughout the function it is defined in.

The ‘const’ keyword, on the other hand, has block scope like ‘let’, but its value cannot be changed once it is assigned. In general, it is recommended to use ‘const’ for values that should not be changed and ‘let’ for values that may change during the program’s execution. ‘var’ is used less frequently in modern JavaScript, but it can still be useful in certain situations where you want to declare a variable with function scope.