WooCommerce Bookings AJAX codes for selection of dates - ajax

Question

My current project need to customisely showing some extra information base on calculations of the dates that has been selected. I have writen a function, and I can't find the AJAX code that the booking system returns the data and calculations base on the valid date to trigger my function.
My function is easy:
function calculate_date_duration() {
var year_1 = document.querySelector('.selection-start-date').getAttribute('data-year');
var month_1 = document.querySelector('.selection-start-date').getAttribute('data-month');
var date_1 = document.querySelector('.selection-start-date a').textContent;
var year_2 = document.querySelector('.selection-end-date').getAttribute('data-year');
var month_2 = document.querySelector('.selection-end-date').getAttribute('data-month');
var date_2 = document.querySelector('.selection-end-date a').textContent;
var day_1 = new Date(year_1, month_1, date_1);
var day_2 = new Date(year_2, month_2, date_2);
console.log(day_1);
console.log(day_2);
var day_selected = day_2.getTime() - day_1.getTime();
var date_duration = parseInt(day_selected / (1000 * 60 * 60 * 24)) +1;
console.log(date_duration);
var display_pane = document.querySelector('.wc-bookings-booking-cost');
display_pane.innerHTML = display_pane.innerHTML + '<br>Total booking cost:<strong><span class="woocommerce-Price-amount amount"><bdi><span class="woocommerce-Price-currencySymbol">$</span>' + (date_duration*120) + '</bdi></span></strong>';}

Answer 1

The date select duration ajax is in wp-content/plugins/woocommerce-bookings/dist/frontend.js, search success, the last one in this file is the codes after validating the selected duration.