How do you use the typeof operator to check if a variable is a boolean in JavaScript?

Omnath Dubey 1/30/2024 01:40:00 AM

In JavaScript, you can use the `typeof` operator to check the type of a variable. To specifically check if a variable is a boolean, you can compare the result of `typeof` with the string `"boolean"`. Here's an example:

let myVariable = true;

if (typeof myVariable === "boolean") {
console.log("myVariable is a boolean.");
} else {
console.log("myVariable is not a boolean.");
}

In this example, `typeof myVariable === "boolean"` checks if the type of `myVariable` is equal to the string "boolean". If it is, the code inside the `if` block is executed, indicating that `myVariable` is a boolean. Otherwise, the `else` block is executed.

It's important to note that the `typeof` operator returns a string representing the type of the operand. Possible values include "undefined", "boolean", "number", "string", "bigint", "object", "function", and "symbol". Using `===` ensures both the type and value are compared.

Here's another example with a variable that is not a boolean:

let anotherVariable = "Hello, world!";

if (typeof anotherVariable === "boolean") {
console.log("anotherVariable is a boolean.");
} else {
console.log("anotherVariable is not a boolean.");
}

In this case, the output will be "anotherVariable is not a boolean" because `anotherVariable` is a string, not a boolean.

JavaScript