Transaction Rule Script (TRS) adding a 9% per item California State sales tax

addNinePercentPerItemCaliforniaStateSalesTax.js

function addNinePercentPerItemCaliforniaStateSalesTax(transaction) {
  var cr_account = arguments.length <= 1 || arguments[1] === undefined ? "DannysMarket" : arguments[1];

  // Test if cr_account is not defined in nested objects, if true return original object
  var cr_accountNotDefine = false;
  transaction.transaction_item.forEach(function (item) {
    if (item.cr_account == null) {
      cr_accountNotDefine = true;
    }
  });
  if (cr_accountNotDefine) {
    return transaction;
  }

  // Remove any existing “9% state sales tax” item to avoid duplicating objects in the array
  var cr_accountItems = transaction.transaction_item.filter(function (item) {

    return item.name !== "9% state sales tax";
  });

  // Add 9% sales tax.
  var salesTaxValue = 0;
  cr_accountItems.forEach(function (item) {
    if (item.cr_account == cr_account) {
      salesTaxValue = salesTaxValue + item.value * item.quantity * 0.09;
    }
  });

  // Add “9% state sales tax” item
  cr_accountItems.push({
    db_account: transaction.db_author,
    cr_account: "StateOfCalifornia",
    quantity: "1",
    units_measured: "",
    unit_of_measurement: "",
    value: salesTaxValue.toFixed(3),
    name: "9% state sales tax"
  });

  transaction.transaction_item = cr_accountItems;

  // Test if db_account of all transaction items match db_author of transaction
  transaction.transaction_item.forEach(function (item) {
    if (item.db_account != transaction.db_author) {
      item.db_account = transaction.db_author;
    }
  });

  return transaction;
};

got it .. thank you