Redux - reducer not getting called

Not the OP's question but for people who just searched Google for "reducer not getting called", make sure you call your action creator:

dispatch(action())

not

dispatch(action)

You have to pass in the action, not the action creator. With useSelect in Redux Toolkit I usually don't have parens in the arg so I forgot to put the parents in the call to dispatch.

You should combine existing state with the new action payload in reducer-add-name.js instead of just returning the payload i.e.

return Object.assign({}, state, {
    todos: [
      ...state,
      {
        action.payload
      }
    ]
  })    

I think your action hasn't been dispatched.

In your input.js On button tag, change

onClick={() => addName(document.getElementById('name-input').value)}

to

onClick={() => this.props.addName(document.getElementById('name-input').value)}

Thing is action should be passed through mapDispatchToProps and 'bindActionCreators(actions, dispatch)' will wrap your action with 'dispatch', and pass through your component via props 'addName'. (as defined in your mapDispatchToProps)

An action alone is like a bullet (just return object) you will need something to fire it (dispatch)

In your case

import {addName} from '../actions/index' <--- a bullet

has been declared and your onClick, without dispatch, it would only return a mere object, not dispatching it to reducer.

addName() // <--- Just a bullet

But

this.props.addName() // <--- bullet with a gun

is from mapDispatchToProps / bindActionCreators... it has dispatch() wrapped around, that is the one we would use.