Knack: Update Equation With Connected Record

custom_code_equation.js

var scene_key = 'scene_1'

var view_key = 'view_36'

var name_field_key = 'field_1'

var price_field_key = 'field_39'

var connected_record_field_key = 'field_30'

var quantity_field_key = 'field_31'

var equation_total_field = 'field_50'

var quantity_selector = 'input#' + quantity_field_key

var equation_total_selector = '#kn-input-' + equation_total_field + ' p.kn-equation'

var connected_record_selector = '#connection-picker-chosen-'+ connected_record_field_key +' .chzn-results li'

var currency = '$'

var connected_records;
    
// async get records
getConnectedRecords(scene_key, view_key, function(records) {
	
  	connected_records = records;
});

$(document).on('knack-view-render.view_10', function(event, scene) {
  
  // hide connected table
  // could be on a separate page to avoid doing this
  $('#view_36').hide();
  
  $(quantity_selector).change(function() {

    calculateTotal(connected_records, $(connected_record_selector + '.result-selected').text())  
  })
	
  $(connected_record_selector).click(function() {
  	
	calculateTotal(connected_records, $(this).text())
  })
})

function calculateTotal(connected_records, connected_record_name) {
    
    var selected_connected_record = connected_records.find(function(record) {
		
      return connected_record_name === record[name_field_key];
	})
    
    if (!selected_connected_record) { return }
    
    var selected_connected_record_price = selected_connected_record[price_field_key + '_raw'];
    
    var quantity = $(quantity_selector).val();
  
  	if (quantity < 1) { return }
    
	var price = selected_connected_record_price * quantity; 
    
    var formatted_price = currency + price.toString()
    
    // setting timeout to update after equation updates
	setTimeout(function() {$(equation_total_selector).text(formatted_price)}, 100)
}

function getConnectedRecords(scene_key, view_key, cb) {

  var connected_records;
  
  $.ajax({
    url: 'https://api.knack.com/v1/pages/'+ scene_key +'/views/'+ view_key +'/records',
    type: 'GET',
    headers: {
      'Authorization': Knack.getUserToken(),
      'X-Knack-Application-Id': Knack.application_id,
      'Content-Type': 'application/json'
    },
    success: function(data) {

      connected_records = data.records;
      
      return cb(connected_records)     
    }
  });
}