odoo-pos-inherit
In this repo i inherit the pos module and added QR code to pos receipt
1- Create new Odoo Module using command line
$ python odoo-bin scaffold <module name> <where to put it>
2- Inherit OrderReceipt JS Screen in odoo
1 - Create new js class and put this code that defin a function referenced to
odoo.define('point_of_sale.OrderReceipt', function (require) {
'use strict';
const PosComponent = require('point_of_sale.PosComponent');
const Registries = require('point_of_sale.Registries');
function myFunction(text) {
return text
}
class OrderReceipt extends PosComponent {
constructor() {
console.log("eslam faisal constructor")
super(...arguments);
this._receiptEnv = this.props.order.getOrderReceiptEnv();
}
willUpdateProps(nextProps) {
this._receiptEnv = nextProps.order.getOrderReceiptEnv();
}
get receipt() {
return this.receiptEnv.receipt;
}
clientName(receipt) {
return receipt.client.name
}
get orderlines() {
return this.receiptEnv.orderlines;
}
get paymentlines() {
return this.receiptEnv.paymentlines;
}
get isTaxIncluded() {
return Math.abs(this.receipt.subtotal - this.receipt.total_with_tax) <= 0.000001;
}
get receiptEnv() {
return this._receiptEnv;
}
isSimple(line) {
return (
line.discount === 0 &&
line.is_in_unit &&
line.quantity === 1 &&
!(
line.display_discount_policy == 'without_discount' &&
line.price < line.price_lst
)
);
}
}
OrderReceipt.template = 'OrderReceipt';
Registries.Component.add(OrderReceipt);
return OrderReceipt;
});
2- Add new Order Receipt that you created recently to JS directory in your module 
3- Create a #data.xml file to xpath the new JS file screen and define it in manifest.py file and make the module depends on point_of_sale
xml version="1.0" encoding="utf-8"?>
<odoo>
<data>
<template id="assets" inherit_id="point_of_sale.assets">
<xpath expr="//script[@src='/point_of_sale/static/src/js/Screens/ReceiptScreen/OrderReceipt.js']"
position="replace">
<script type="text/javascript" src="/pos_inherit/static/src/js/OrderReceipt.js"/>
xpath>
template>
data>
odoo>
3- Inherit OrderReceipt XML file
1 - Create new xml file pos_receipt.xml and register it in manifest.py but in qweb section 
2- inherit pos receipt screen xml by xpath 3 - use t tag for access JS values 4 - use api.qrserver.com public api to get the QR code with given data
Served for
xml version="1.0" encoding="UTF-8"?>
<templates id="template" xml:space="preserve">
<t t-name="OrderReceipt" t-inherit="point_of_sale.OrderReceipt" t-inherit-mode="extension" owl="1">
<xpath expr="//div[hasclass('pos-receipt-order-data')]" position="after">
<img id="qr_image"
style="width:180px;height:180px; margin-left:60px;margin-top:16px;"/>
<script>
let image = document.getElementById('qr_image');
let qrData = " :اسم المورد "+ " <t t-esc="receipt.company.name"/>";
qrData += "%0A";
qrData += "الرقم الضريبي: "+ "<t t-esc="receipt.company.vat"/>";
qrData += "%0A";
qrData += ":التاريخ "+ "<t t-esc="receipt.date.localestring"/>";
qrData += "%0A";
qrData += "المبلغ الكلي: "+ "<t t-esc="receipt.total_with_tax"/>";
qrData += "%0A";
qrData += "العميل: "+ "<t t-esc="receipt.client.name"/>";
qrData += "%0A";
qrData += "الرقم الضريبي: "+ "<t t-esc="receipt.client.vat"/>";
image.src = "https://api.qrserver.com/v1/create-qr-code/?data="+qrData;
script>
xpath>
<xpath expr="//div[hasclass('cashier')]" position="after">
<div>Served for <t t-esc="receipt.client.name"/>div>
xpath>
t>
templates>
#Finally then create pos order with client 
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