Thanks for your answer.

I haven't been able to inherit the PosComponent.js file, but I did found an other way to solve my issue, but it's not quiet the solution to this question.

I found out that i can inherit / override functions in components that is in the Registries class like so:

const PaymentScreen = require('point_of_sale.PaymentScreen');

const Registries = require('point_of_sale.Registries');

const MyPaymentScreen = PaymentScreen =>

class extends PaymentScreen {

constructor (){

super(...arguments);

}

onClick() {

// your code here

console.log('button clicked)

}

};

Registries.Component.extend(PaymentScreen, MyPaymentScreen);

return MyPaymentScreen;

});

<?xml version="1.0" encoding="UTF-8"?>

<templates id="template" xml:space="preserve">

<t t-name="MyPaymentScreen" owl="1">

<div class="ticket-button" t-att-class="{ highlight: props.isTicketScreenShown }" t-on-click="onClick">

<!-- <div class="with-badge" t-att-badge="count"> -->

<i class="fa fa-credit-card" aria-hidden="true"></i>

<!-- </div> -->

</div>

</t>

<t t-inherit="point_of_sale.Chrome" t-inherit-mode="extension">

<xpath expr="//OrderManagementButton" position="before">

<MyPaymentScreen t-if="env.pos.config.use_proxy" />

</xpath>

</t>

</templates>