Building Front-End Web Applications with Plain JavaScript/

...

/

JavaScript Basics

JavaScript Basics

Let’s learn the basics of JS data types.

We'll cover the following...

Data types

JavaScript has three primitive datatypes–string, number, and boolean. There are five reference datatypes–Object, Array, Function, Date, and RegExp. Arrays, functions, dates, and regular expressions are special types of objects, but conceptually, dates and regular expressions are primitive data values and happen to be implemented in the form of wrapper objects.

Below, we have an example of JS data types:

Press + to interact
  let string = "Johnson";                             // String
  let number = 16;                                    // Number
  let bool = true;                                    // Boolean
  let object = {firstName:"John", lastName:"Doe"};    // Object
  let array = ['Jim', 'Shawna'];                      // Array
  function func() { return (5 * 19); }                // Function
  let date = new Date()                               // Date
  console.log("String is: "   + string)
  console.log("Number is: "   + number)
  console.log("Object is: "   + object.firstName + " " + object.lastName)
  console.log("Array is: "    + array)
  console.log("Function is: " + func())
  console.log("Date is: "     + date.toUTCString())

String data

A string is a sequence of Unicode characters. String literals, like "Hello world!", 'A3F0', or the empty string "" are enclosed in single or double quotes. Two string expressions can be concatenated with the + operator and checked for equality with the triple equality operator.

The number of characters in a string can be obtained by applying the length attribute to a string. The following ...