How to Get the Class Name of an Object in JavaScript

Use the name Property

You can use the name property of the object's constructor function to get the name of the class that is used to instantiated the object. Let's take a look an example:

<script>    
class Rectangle {
    // Class constructor
    constructor(length, width) {
        this.length = length;
        this.width = width;
    }
    
    // Class method
    getArea() {
        return this.length * this.width;
    }
}
 
var rectObj = new Rectangle(5, 10);
alert(rectObj.getArea()); // Outputs: 50
alert(rectObj.constructor.name) // Outputs: Rectangle
</script>