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/What Are Var, Let, and Const Keywords in JavaScript?
What Are Var, Let, and Const Keywords in JavaScript?
Learn how to define variables, as well as the differences between the var, let, and const keywords used to declare variables.
We'll cover the following...
Introduction
To define any variable in JavaScript, there are three keywords: var, let, and const. These keywords can be a bit confusing—let’s get to know them by going over their differences. We’ll start with their scope.
Scope
The scope of a variable defines the accessibility of that variable in the program. In other words, it specifies the area in the program/code where a particular variable can be accessed.
var |
let |
const |
|---|---|---|
Variables declared with var are in the function scope. |
Variables declared as let are in the block scope. |
Variables declared as const are also in the block scope. |
Look at the below code snippets to see this:
{// Define a var variablevar variable_1 = "Hello";// Access and print the value of variable_1console.log(variable_1);}// Access and print the value of variable_1console.log(variable_1);
Explanation:
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When executing the code in the
vartab, we will see that thevariable_1is accessible inside and outside of the block. ...