#Basic data types in javascript code#

The second function in the example above doesn’t wait for the first function to finish. Therefore, setTimeout () is an example of a callback function. Result in console // This is second // This is first (after 3000 milliseconds or 3 seconds)Īs we see above when we call the setTimeout function, the hello1 () function doesn’t get executed until 3000 milliseconds are completed. setTimeout calls the function after a certain number of specified milliseconds. Now we will use the setTimeout function on the hello1 function while calling it. Result in the console // This is first // This is second Here the callback function is passed as an argument to the hello function. A callback function is created by passing it as a parameter to another function and then calling it back immediately after an event or action has been performed. It protects us from errors and issues while assisting us in writing asynchronous JavaScript code. Callbacks ensure that a function will execute immediately following the completion of a job rather than before it. We refer to this as asynchronous programming.

#Basic data types in javascript code#

However, there are some situations when code executes (or must execute) both post-event and not sequentially. JavaScript executes code in a top-down, sequential fashion. A function is also a type of object, hence we can pass a function as a parameter to other functions. We can pass objects as parameters to functions in JavaScript. 1Ĭonsole.log( 'The name is' + ' ' + this.name + ' ' + last_name) If we want to access the properties of an object inside a method we have to use the “this” keyword. JavaScript has various built-in methods as well.

The object student consists of the method greet. Methods are represented as object attributes and are functions. Object - It is a collection of data consisting of key-value pairs (non-primitive data type).Įxample: const student = Example: A function to multiply two numbers: 1Īn object’s property that has a function declaration is known as a JavaScript method. Symbol - A symbol is an unchangeable, singular primal value (non-primitive data type). Undefined - It represents a variable that is not assigned. You add n to the end of the number literal to create a BigInt.īoolean - It stores either true or false. Number - It stores a decimal or non-decimal number.īigInt - It stores numbers greater than 253-1 which are not permissible in number data type. JavaScript supports eight basic data types. In JavaScript, there are two main kinds of data types. JavaScript offers many data types to store various sorts of values. In this tutorial, we will learn about JavaScript’s various data types and different types of functions. They don’t require any further setup or compilation to function.

Plain text is used to deliver and run scripts. They can be included directly in the HTML of a web page and executed immediately when the page loads.

Scripts are what this language refers to as programs. Every modern web browser already has it preinstalled and it can be used to create front-end and back-end apps using a variety of frameworks and libraries. One of the most popular programming languages nowadays is JavaScript.