React useReducer Hook fires twice / how to pass props to reducer?

Question

FOREWORD / DESCRIPTION

I am trying to use React\'s new hooks feature for an e-commerce website that I am building, and have been having an issue wor

Answer 1

An example based on Ryans excellent answer.

  const memoizedReducer = React.useCallback((state, action) => {
    switch (action.type) {
      case "addRow":
        return [...state, 1];
      case "deleteRow":
        return [];
      default:
        throw new Error();
    }
  }, []) // <--- if you have vars/deps inside the reducer that changes, they need to go here

  const [data, dispatch] = React.useReducer(memoizedReducer, _data);