Difference between Let, Const and Var. Write code and explain.

Question

Accepted Answer

Let, Const, and Var are used to declare variables in JavaScript with different scoping and reassignment abilities.

Var has function scope and can be redeclared and reassigned.
Let has block scope and can be reassigned but not redeclared.
Const has block scope and cannot be reassigned or redeclared.

Accepted Answer

let, const, and var are all keywords used to declare variables in JavaScript. However, there are some important differences between them in terms of scope, hoisting, and reassignment.

var: var was the original way to declare variables in JavaScript, and it has some unique behavior that can lead to bugs. Variables declared with var are function-scoped, which means that they are accessible throughout the entire function in which they are declared. If a variable is declared with var inside a block statement (e.g. if, for, while), it is accessible throughout the entire function, not just the block statement. Additionally, var variables are hoisted to the top of their scope, which means that they can be accessed before they are declared.

let: let was introduced in ES6 as a replacement for var. Variables declared with let are block-scoped, which means that they are only accessible within the block in which they are declared. let variables are not hoisted, so they cannot be accessed before they are declared. Additionally, let variables can be reassigned, but they cannot be re-declared within the same scope.

const: const is also introduced in ES6 and is used to declare variables whose values cannot be re-assigned. const variables are also block-scoped and not hoisted. However, the variable itself is not immutable, only its value cannot be changed.

In summary, let and const are generally preferred over var because they provide more predictable and less error-prone behavior. let is used when a variable needs to be reassigned, while const is used when a variable's value should not be changed.

Difference between Let, Const and Var. Write code and explain.

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