Math.random is forbidden in redux paradigm

[HawkeyePierce89]

https://github.com/developit/preact-redux-example/blob/66590ec786df463b790b0603361ef21e3e178736/src/store.js#L6

the reducer must be pure. Given the same arguments, it should calculate the next state and return it. No surprises. No side effects. No API calls. No mutations. Just a calculation

https://redux.js.org/basics/reducers#handling-actions