Check If a Variable Is of Function Type

Check if a variable is of function type

When working with JavaScript, it is often necessary to check the type of a variable. One common scenario is when you need to determine if a variable is of function type. In this blog post, we will explore different solutions to this problem.

Solution 1: Using the typeof operator

The simplest way to check if a variable is of function type is by using the typeof operator. The typeof operator returns a string that represents the type of the operand. For a function, it returns "function".

const myFunction = () => {
  // Function body
};

console.log(typeof myFunction === "function"); // Output: true

In the above example, we declare a variable myFunction and assign an arrow function to it. We then use the typeof operator to check if the variable is of function type. The output will be true.

Solution 2: Using the instanceof operator

Another way to check if a variable is of function type is by using the instanceof operator. The instanceof operator tests if an object has in its prototype chain the prototype property of a constructor.

const myFunction = () => {
  // Function body
};

console.log(myFunction instanceof Function); // Output: true

In the above example, we declare a variable myFunction and assign an arrow function to it. We then use the instanceof operator to check if the variable is of function type. The output will be true.

Solution 3: Using the Object.prototype.toString() method

The Object.prototype.toString() method returns a string representing the object. By calling this method on a function, we can determine if a variable is of function type.

const myFunction = () => {
  // Function body
};

console.log(Object.prototype.toString.call(myFunction) === "[object Function]"); // Output: true

In the above example, we declare a variable myFunction and assign an arrow function to it. We then use the Object.prototype.toString() method to check if the variable is of function type. The output will be true.

These are the three different solutions to check if a variable is of function type in JavaScript. Choose the one that best suits your needs and implement it in your code.

Happy coding!