How can we invoke the parent's method, when a child has a method with the same name in JavaScript?

When both parent and child classes have methods with the same name, JavaScript provides several ways to invoke the parent's method from the child class or externally.

Syntax

To call a parent method when overridden by a child class:

// From within child class
super.methodName()

// From outside using call()
ParentClassName.prototype.methodName.call(childObject)

Using super Keyword (Recommended)

The super keyword is the modern way to call parent methods from within a child class:

class Parent {
    constructor(value) {
        this.value = value;
    }
    
    display() {
        return `Parent class value: ${this.value}`;
    }
}

class Child extends Parent {
    constructor(value1, value2) {
        super(value1);
        this.value2 = value2;
    }
    
    display() {
        // Call parent method using super
        return `${super.display()}, Child class value: ${this.value2}`;
    }
}

const childObj = new Child(10, 20);
console.log(childObj.display());

Parent class value: 10, Child class value: 20

Using call() Method

You can also invoke the parent method externally using the call() method:

class Parent {
    constructor(value) {
        this.value = value;
    }
    
    display() {
        return `Parent class value: ${this.value}`;
    }
}

class Child extends Parent {
    constructor(value1, value2) {
        super(value1);
        this.value2 = value2;
    }
    
    display() {
        return `Child class value: ${this.value2}`;
    }
}

const childObj = new Child(10, 20);

// Call parent method directly
console.log("Parent method:");
console.log(Parent.prototype.display.call(childObj));

// Call child method
console.log("Child method:");
console.log(childObj.display());

Parent method:
Parent class value: 10
Child method:
Child class value: 20

Comparison of Methods

Key Points

? Use super when calling parent methods from within the child class
? Use call() method when you need to invoke parent methods externally
? The super keyword automatically binds the correct this context

Conclusion

The super keyword is the recommended approach for calling parent methods from within child classes. Use call() method when you need external access to parent functionality.