pybricks-code/src/reducers/editor.ts

import { Ace } from 'ace-builds';
import { Reducer, combineReducers } from 'redux';
import { CurrentEditorAction, EditorActionType } from '../actions/editor';

type CurrentEditSession = Ace.EditSession | null;

const current: Reducer<CurrentEditSession, CurrentEditorAction> = (
    state = null,
    action,
) => {
    switch (action.type) {
        case EditorActionType.Current:
            return action.editSession || null;
        default:
            return state;
    }
};

export interface EditorState {
    current: CurrentEditSession;
}
export default combineReducers({ current });