JavaScript Relational Operators are used to compare their operands and determine the relationship between them. They return a Boolean value (true or false) based on the comparison result.
Types of Relational Operators
These are two types of relational operators, these are:
We will explore all the above operators along with their basic implementation with the help of examples.
JavaScript in Operator
The in-operator in JavaScript checks if a specified property exists in an object or if an element exists in an array. It returns a Boolean value.
Syntax:
prop in object
Example 1: Here is the basic example of using in operator.
let languages = [ "HTML" , "CSS" , "JavaScript" ];
// true (index 1 exists in the array) console.log(1 in languages);
// false (index 3 doesn't exist in the array) console.log(3 in languages);
|
true false
Example 2: In this example, we are using in operator to check if the “name” property exists (true) and if the “address” property doesn’t exist (false).
const Data = { name: "Rahul" ,
age: 21,
city: "Noida"
}; // true ("name" property exists in the object) console.log( "name" in Data);
// false ("gender" property doesn't exist in the object) console.log( "address" in Data);
|
true false
JavaScript instanceof Operator
The instanceof operator in JavaScript tests if an object is an instance of a particular class or constructor, returning a Boolean value.
Syntax:
let gfg = objectName instanceof objectType
Example 1: In this example, we are using instanceof operator.
let languages = [ "HTML" , "CSS" , "JavaScript" ];
console.log(languages instanceof Array);
console.log(languages instanceof Object);
console.log(languages instanceof String);
console.log(languages instanceof Number);
|
true true false false
Example 2: In this example, the instanceof operator checks if myString is an instance of Object, Date, or String, and if myDate is an instance of Date, Object, or String.
let myString = new String();
let myDate = new Date();
console.log(myString instanceof Object);
console.log(myString instanceof Date);
console.log(myString instanceof String);
console.log(myDate instanceof Date);
console.log(myDate instanceof Object);
console.log(myDate instanceof String);
|
true false true true true false