Data Types and Num Type Conversion
In JavaScript, there are several data types, including:
Number - used to represent numeric values
String - used to represent text values
Boolean - used to represent true/false values
Null - used to represent the intentional absence of any object value
Undefined - used to represent the absence of a defined value
Object - used to represent a collection of related data and functionality
Symbol - used to represent a unique identifier
Type Conversions
To convert one data type to another, you can use type conversion. In JavaScript, there are two types of type conversion: explicit and implicit.
Explicit type conversion involves converting a value from one type to another using built-in functions. Here are some examples:
Number to String: String(42)
String to Number: Number("42")
Boolean to String: String(true)
String to Boolean: Boolean("true")
Implicit type conversion, also known as type coercion, happens automatically when JavaScript expects a certain data type but receives a different one. For example:
Adding a number and a string: 5 + "5" will result in the string "55"
Comparing a number and a string: 5 == "5" will return true.
Example
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Data Types and Type Conversion</title>
</head>
<body>
<p>Open the console to see the output</p>
<script>
// Define variables with different data types
let num = 42;
let str = "hello";
let bool = true;
let obj = { name: "John", age: 30 };
let sym = Symbol("id");
// Use console.log to print the variables and their types
console.log(num, typeof num);
console.log(str, typeof str);
console.log(bool, typeof bool);
console.log(obj, typeof obj);
console.log(sym, typeof sym);
// Use explicit type conversion to convert data types
let numStr = String(num);
let strNum = Number(str);
let boolStr = String(bool);
let strBool = Boolean(str);
console.log(numStr, typeof numStr);
console.log(strNum, typeof strNum);
console.log(boolStr, typeof boolStr);
console.log(strBool, typeof strBool);
// Use implicit type conversion to concatenate a number and a string
let result = num + str;
console.log(result, typeof result);
// Use strict equality to compare a number and a string
console.log(num === str);
</script>
</body>
</html>