Use typeof to Check the Type of a Variable
Typeof in JavaScript is an operator used for type checking and returns the data type of the operand passed to it.
Debugging is the process of finding and fixing errors or bugs in the source code of any software. When software does not work as expected, computer programmers study the code to determine why any errors occurred.
What is JSON used for? JavaScript Object Notation (JSON) is a standard text-based format for representing structured data based on JavaScript object syntax. It is commonly used for transmitting data in web applications (e.g., sending some data from the server to the client, so it can be displayed on a web page, or vice versa).
What is a String in JavaScript? A JavaScript string stores a series of characters like "John Doe". A string can be any text inside double or single quotes: let carName1 = "Volvo XC60"; let carName2 = 'Volvo XC60'; Try it Yourself »
What is a JavaScript Object? JavaScript is designed on a simple object-based paradigm. An object is a collection of properties, and a property is an association between a name (or key) and a value. A property's value can be a function, in which case the property is known as a method.
What is Boolean in JavaScript? In JavaScript, a boolean value is one that can either be TRUE or FALSE. If you need to know “yes” or “no” about something, then you would want to use the boolean function. It sounds extremely simple, but booleans are used all the time in JavaScript programming, and they are extremely useful.
What is the Null in JavaScript? The null value represents the intentional absence of any object value. It is one of JavaScript's primitive values and is treated as falsy for boolean operations.
What is the Undefined in JavaScript? A variable that has not been assigned a value is of type undefined . A method or statement also returns undefined if the variable that is being evaluated does not have an assigned value. A function returns undefined if a value was not returned.
What is JavaScript Number? The Number() method converts a value to a number. If the value cannot be converted, NaN is returned.
What is JavaScript Symbol? The JavaScript Symbol is a primitive data type, just like Number, String, Boolean, etc. It represents a unique identifier and can be used in various ways. Symbols are used to create object properties, for example, when you want to assign a unique identifier to an object.
What is a Biglnt in JavaScript? JavaScript BigInt variables are used to store big integer values that are too big to be represented by a normal JavaScript Number.
What is JavaScript console log? The console.log() method outputs a message to the web console. The message may be a single string (with optional substitution values), or it may be any one or more JavaScript objects.
How to see JavaScript console logs? With the Chrome browser open, right-click anywhere in the browser window and select Inspect from the pop-up menu. By default, the Inspect will open the "Elements" tab in the Developer Tools. Click on the "Console" tab which is to the right of "Elements".