dependency inversion implementation in javascript

Question

the book "Clean Architecture" said:

When using dynamically typed languages like Ruby and Python ... dependency inversion does not require either the declaration or the inheritance of interfaces.

but I don't quite understand it, the book didn't provide any example

my understanding of the DIP is that if ClassA depends on ClassB violating the DIP, we can introduce an InterfaceC, then we get something like

ClassA ---> InterfaceC <--- ClassB

I've also looked at some examples on the internet, like this one that attempts dependency injection between PurchaseHandler and PayPal , https://duncan-mcardle.medium.com/solid-principle-5-dependency-inversion-javascript-7b054685f7cb

class PurchaseHandler {
    processPayment(paymentDetails, amount) {
        const paymentSuccess = PaymentHandler.requestPayment(
            paymentDetails,
            amount
        );

        if (paymentSuccess) {
            // Do something
            return true;
        }

        // Do something
        return false;
    }
}

class PaymentHandler {
    requestPayment(paymentDetails, amount) {
        // Complicated, PayPal specific logic goes here
        return PayPal.requestPayment(paymentDetails, amount);
    }
}

However, it seems to simply add a layer between them, resulting in this dependency graph:

PurchaseHandler ---> PaymentHandler ---> PayPal

no inversion is happening here...

dependency inversion implementation in javascript

0 Answers0