Learning Redux

Defining a generic initial state

Now that we know what our history object will look like, all that's left to do is creating the initial state:

1. Consider the following line:

const initialState = {} // TODO

Replace it with our new history object:

const initialState = {  past: [],  present: ..., // TODO  future: []}

2. There is still a problem--how do we set a generic initial state as present? We do not know what the reducer's internal state looks like. However, we can simply call the reducer (which was passed as an argument to our undoable higher-order function) with an undefined state and an empty action to trigger it to populate its initial state. Update the initialState definition:

const initialState = {  past: [],  present: reducer(undefined, ...