onlinecode

The `typeof` Operator in JavaScript

onlinecode

The `typeof` Operator in JavaScript

The `typeof` Operator in JavaScript

In this post, we will give you information about The `typeof` Operator in JavaScript. Here we will give you detail about The `typeof` Operator in JavaScript And how to use it also give you a demo for it if it is necessary.

The typeof operator returns the type of a given variable as a string.

typeof 42; // 'number'
typeof 'test'; // 'string'
typeof true; // 'boolean'
typeof (void 0); // 'undefined'
typeof BigInt('1234'); // 'bigint'
typeof Symbol('foo'); // 'symbol'
typeof ({ answer: 42 }); // 'object'
typeof function() {}; // 'function'

// As far as 'typeof' is concerned, all objects are the same.
class MyClass {}
typeof (new MyClass()); // 'object'

Here’s the general idea: the typeof operator returns which of the 8 JavaScript data types a given value is. There’s one key exception to this rule: null.

With null

The one big gotcha with typeof is that typeof null === 'object'. There is a historical reason for this behavior, and a proposal to change this behavior was rejected, so it looks like JavaScript is stuck with this quirk.

The workaround to check whether a value is actually an object with typeof is to check whether the type is 'object' and the value
is not strictly equal to null.

function isObject(v) {
  return typeof v === 'object' && v !== null;
}

Error Cases

The typeof operator can throw an error if you use it on a block scope variable before you define it.

// Throws 'ReferenceError: v is not defined'
console.log(typeof v);

let v;

This behavior only applies for block scoped variables. For example, if you don’t define v at all, the above script will work fine.

console.log(typeof v); // 'undefined'

//let v;

Block scoped variables are the only case where typeof throws an error. Otherwise, typeof will always succeed.

See also  Empty Objects are Truthy in JavaScript?

More Fundamentals Tutorials

  • 3 Patterns to Merge Arrays in JavaScript
  • Convert a BigInt to a Number in JavaScript
  • The parseInt Function in JavaScript
  • The toFixed() Function in JavaScript
  • The Nullish Coalescing Operator ?? in JavaScript
  • Implementing Tuples in JavaScript
  • Convert a JavaScript Enum to a String

JavaScript Fundamentals for  The `typeof` Operator in JavaScript 

JavaScript is a programming language that is used to create interactive web pages. It is a client-side scripting language, which means that it runs on the user’s browser. JavaScript can be used to add animation, interactivity, and functionality to web pages.

Here are some of the fundamentals of JavaScript:

See also  Get the Last Element in an Array in JavaScript

These are just some of the fundamentals of JavaScript. There are many other concepts that you can learn as you continue to develop your skills.

Here are some resources that you can use to learn more about JavaScript:

See also  Validate Emails using Regex in JavaScript

I hope this helps for The `typeof` Operator in JavaScript !

Here are some additional tips for learning JavaScript:

With a little practice, you’ll be able to learn JavaScript and start building amazing web applications.

Hope this code and post will helped you for implement The `typeof` Operator in JavaScript – onlinecode. if you need any help or any feedback give it in comment section or you have good idea about this post you can give it comment section. Your comment will help us for help you more and improve us. we will give you this type of more interesting post in featured also so, For more interesting post and code Keep reading our blogs

For More Info See :: laravel And github

Exit mobile version