Redux-toolkit: Object.keys: argument is not an Object in redux-starter-kit.esm.js

[paul-mcgrath]

Hi there,

I'm having an issue using this project with IE11, specifically with this error message in the redux-starter-kit.esm.js file:

Object.keys: argument is not an Object

The issue occurs in the following method on the third line :
```function _objectSpread(target) {
for (var i = 1; i < arguments.length; i++) {
var source = arguments[i] != null ? arguments[i] : {};
var ownKeys = Object.keys(source); // <-- error occurs here

if (typeof Object.getOwnPropertySymbols === 'function') {
  ownKeys = ownKeys.concat(Object.getOwnPropertySymbols(source).filter(function (sym) {
    return Object.getOwnPropertyDescriptor(source, sym).enumerable;
  }));
}

ownKeys.forEach(function (key) {
  _defineProperty(target, key, source[key]);
});

}

return target;
}
```

From digging a bit deeper, it seems to try and call Object.keys on a value of false, which then fails in IE11.

The current behaviour in Chrome is to return an empty array when calling Object.keys() on a non-object, but polyfilling IE11's Object.keys() method has so far been unsuccessful.

Should this starter kit work with IE11 out of the box, or is there some guidance on compatibility?

[markerikson]

Hmm. I'll be honest and say I've put zero thought into browser compat issues so far.

That particular chunk of code appears to be a Babel polyfill for the object spread operator.

What input and stack trace is leading to that particular edge case getting hit?

[dcp12345678]

@markerikson , I got this same error today. In your code for configureStore, you are calling _objectSpread. That is where the blow up happens when running on IE11.

I tried the react-app-polyfill but it made no difference in this case.

  if (devTools) {
    finalCompose = composeWithDevTools(_objectSpread({    // <--- here's the call
      // Enable capture of stack traces for dispatched Redux actions
      trace: !IS_PRODUCTION
    }, _typeof(devTools) === 'object' && devTools));
  }

[markerikson]

Again, to be clear, this is not "our code". That is a Babel build artifact. The actual source is:

https://github.com/reduxjs/redux-starter-kit/blob/987c21ec154ff56e3d6cbddde55eaeb768f86ce2/src/configureStore.ts#L137-L143

If someone can come up with a fix and file a PR, I'm open to taking it, but this is a very low priority concern to me atm.

[markerikson]

Closing due to lack of actionable feedback.

[realignedtechnologies]

In case anyone comes here via google and is looking for a fix, including the es6-shim resolves the issue.

[felixpaq]

Even simpler fix, just set the devTools option to an empty object in the configureStore

export default configureStore({
  reducer: rootReducer,
  devTools: {}
});