Multiple transactions in a single JavaScript statement

tx-eval.js

function tx(f, vars, opts) {
  opts = opts || {};
  if(!opts.isolation) { opts.isolation = "different-transaction"; }
  //opts.transactionMode = "update"; // Not sure what this does here.
  return xdmp.eval('(' + f.toString() + ')();', vars, opts);
}

tx(
  function() {
    declareUpdate();
    var sem = require("/MarkLogic/semantics.xqy");
    xdmp.documentInsert(sem.uuidString(), {"asdf": "asdf"});
  }
);

transaction(
  function() {
    return fn.count(fn.collection());
  }
);

tx-invokeFunction.sjs

function tx(f, database, modules, root) {
  return function() {
    var outer = arguments; // arguments closure passed into wrapped function
    return xdmp.invokeFunction(
      function() { return f.apply(null, outer); }, // Curry to make it arity zero
      { 
        //database: xdmp.database(database), // TODO: Make this configurable?
        transactionMode: "update-auto-commit", 
        isolation: "different-transaction"
      }
    );
  }
}

// Usage: 
function values(start) {
  var out = [];
  for(var company of cts.values(cts.jsonPropertyReference('Company'), start, ['frequency-order', 'descending', 'limit=25'])) {
    out.push(
      {
        name: company,
        count: cts.frequency(company)
      }
    );
  }
  return out;
}
// Or more transparently, 
//   var values = tx(function(start) {…}); 
//   values('M');
tx(values)('M');