Unable to execute "fibonacci" demo by using napa

environment: macos 10.13.5 node: 10.6.0 napajs: 0.2.3 code

const napa = require('napajs');
const zone = napa.zone.create('zone', { workers: NUMBER_OF_WORKERS });
function fibParallel (n) {
      if (n <= 1) {
        return n;
      }
      var p1 = zone.execute('', 'fibParallel', [n - 1]);
      var p2 = zone.execute('', 'fibParallel', [n - 2]);
      var p3 = zone.execute('', 'fibParallel', [n - 3]);
      var p4 = zone.execute('', 'fibParallel', [n - 4]);
      // Returning promise to avoid blocking each worker.
      return Promise.all([p1, p2, p3, p4]).then(([result1, result2, result3, result4]) => {
        return result1.value + result2.value + result3.value + result4.value;
      });
    }
zone.broadcast(`
    var napa = require("napajs");
    var zone = napa.zone.get("zone");`);
    // Broadcast function declaration of 'fibonacci' to napa workers.
    zone.broadcast(fibParallel.toString());
const num = await zone.execute('', 'fibParallel', [30]);
console.log(num)

And it throw

/Users/swenchan/.n/bin/node[36217]: ../src/node_platform.cc:262:std::shared_ptr node::NodePlatform::ForIsolate(v8::Isolate ): Assertion `data' failed. 1: 0x100033d65 node::Abort() [/Users/swenchan/.n/bin/node] 2: 0x100032dab node::MakeCallback(v8::Isolate, v8::Localv8::Object, char const*, int, v8::Localv8::Value, node::async_context) [/Users/swenchan/.n/bin/node] 3: 0x100090dfa node::NodePlatform::CallOnBackgroundThread(v8::Task, v8::Platform::ExpectedRuntime) [/Users/swenchan/.n/bin/node] 4: 0x100090e55 node::NodePlatform::CallOnForegroundThread(v8::Isolate*, v8::Task*) [/Users/swenchan/.n/bin/node] 5: 0x1005cf3a1 v8::internal::Sweeper::StartSweeperTasks() [/Users/swenchan/.n/bin/node] 6: 0x100599147 v8::internal::MarkCompactCollector::Finish() [/Users/swenchan/.n/bin/node] 7: 0x10056d9b6 v8::internal::Heap::MarkCompact() [/Users/swenchan/.n/bin/node] 8: 0x10056b960 v8::internal::Heap::PerformGarbageCollection(v8::internal::GarbageCollector, v8::GCCallbackFlags) [/Users/swenchan/.n/bin/node] 9: 0x10056a2f8 v8::internal::Heap::CollectGarbage(v8::internal::AllocationSpace, v8::internal::GarbageCollectionReason, v8::GCCallbackFlags) [/Users/swenchan/.n/bin/node] 10: 0x10057683c v8::internal::Heap::AllocateRawWithRetry(int, v8::internal::AllocationSpace, v8::internal::AllocationAlignment) [/Users/swenchan/.n/bin/node] 11: 0x100553bb8 v8::internal::Factory::NewJSArray(v8::internal::ElementsKind, v8::internal::PretenureFlag) [/Users/swenchan/.n/bin/node] 12: 0x100553c92 v8::internal::Factory::NewJSArray(v8::internal::ElementsKind, int, int, v8::internal::ArrayStorageAllocationMode, v8::internal::PretenureFlag) [/Users/swenchan/.n/bin/node] 13: 0x10063b41c v8::internal::JsonStringifier::JsonStringifier(v8::internal::Isolate*) [/Users/swenchan/.n/bin/node] 14: 0x10025c25e v8::internal::Builtin_Impl_JsonStringify(v8::internal::BuiltinArguments, v8::internal::Isolate*) [/Users/swenchan/.n/bin/node] 15: 0x2b0eea90a1dd 16: 0x2b0eea90c5a3 17: 0x2b0eea9d3d62 18: 0x2b0eea9d401d

Anyone who can help me with this?