TypeError: setting a property that has only a getter

[approots]

There is an error that prevents rendering using Firefox 42 on Windows 7:

TypeError: setting a property that has only a getter

The error occurs on line 28 of enhancer/enhancer.js:

Object.assign(reducer,tinyReducer,reducer);

I can fix the error by changing that line to:

Object.assign(reducer,tinyReducer);