EXAMPLES.md

examples

merging

Using compose and next, we can let our reducers only return the keys they have modified, instead of the entire new state.

import {compose} from "horux";
import reducer from "./reducer";

const mergeNext = (state, action, next) => Object.assign(state, next(state))
return compose([
  mergeNext,
  reducer
]);

versioning

In this scenario, we might have several async actions being fired near-simultaneously. Using two extra reducers in the compose chain, we can maintain a version property of the state, and reject any actions that aren't being fired from an up-to-date state.

import {nextIf, withDefault, compose} from "horux";
import reducer from "./reducer";

const verifyVersion = nextIf((state, action) => state.version === action.expectedVersion);
const bumpVersion = (state) => {...state, version: state.version + 1};
const defaultState = {version: 0}

return compose([
  withDefault(defaultState),
  verifyVersion,
  reducer,
  bumpVersion
]);

undoing

Using compose, we can create a proxy reducer that saves the state, and simply returns to an older state if the UNDO_ACTION is supplied

import {compose} from "horux";
import reducer from "./reducer";

const undoable = (undoType = "UNDO_ACTION") => {
  let latestState;
  let undoState;
  return (state, action, next) = {
    if(action.type === undoType) {
      return undoState;
    }
    undoState = latestState;
    latestState = next(state);
    return latestState;
  }
}

return compose([
  undoable("USER_UNDID"),
  reducer;
]);