Best Way to Check If Variable is a Function in JavaScript

To check if a variable is a function in JavaScript, you can use the typeof operator.

Here’s an example:

function exampleFunction() {
  // function code goes here
}

if (typeof exampleFunction === 'function') {
  console.log('exampleFunction is a function!');
}
Code language: JavaScript (javascript)

The typeof operator returns the type of a variable or expression. In this case, it will return 'function' if the variable is a function.

Alternatively, you can use the isFunction() method from the underscore.js library, which is a utility library for JavaScript.

Here’s an example:

function exampleFunction() {
  // function code goes here
}

if (_.isFunction(exampleFunction)) {
  console.log('exampleFunction is a function!');
}
Code language: JavaScript (javascript)

The isFunction() method returns true if the argument is a function, and false otherwise. It’s a convenient way to check if a variable is a function without using the typeof operator.