ptzagk / redux-ignore

:recycle: higher-order reducer to ignore redux actions

redux-ignore

higher-order reducer to ignore redux actions

can be used to avoid performance problems in large apps by skipping reducer subtrees

Installation

npm install --save redux-ignore

API

import { ignoreActions, filterActions } from 'redux-ignore';

ignoreActions(reducer, [ARRAY_OF_ACTIONS])
ignoreActions(reducer, (action) => !action.valid)

filterActions(reducer, [ARRAY_OF_ACTIONS])
filterActions(reducer, (action) => action.valid)

Ignoring Actions

redux-ignore is a reducer enhancer (higher-order reducer), it provides the ignoreActions function, which takes an existing reducer and either:

• An array of actions to be ignored, or...
• A predicate function for filtering out actions.

Firstly, import redux-ignore:

// Redux utility functions
import { combineReducers } from 'redux';
// redux-ignore higher-order reducer
import { ignoreActions } from 'redux-ignore';

Then, add ignoreActions to your reducer(s) like this:

combineReducers({
  counter: ignoreActions(counter, [INCREMENT_COUNTER])
});

Now you won't be able to increment the counter anymore, because the INCREMENT_COUNTER action is ignored.

Alternatively, you can ignore actions via a predicate function:

combineReducers({
  counter: ignoreActions(counter, (action) => action.type === INCREMENT_COUNTER)
});

Filtering Actions

You can also use filterActions to only accept actions that are declared in an array, or that satisfy the predicate function:

import { combineReducers } from 'redux';
import { filterActions } from 'redux-ignore'; // pull in the filterActions function
import { STAY_COOL, KEEP_CHILLIN } from './actions';
import { counter, notACounter } from './reducers';

combineReducers({
  counter: filterActions(counter, (action) => action.type.match(/COUNTER$/)), // only run on actions that satisfy the regex
  notACounter: filterActions(notACounter, [STAY_COOL, KEEP_CHILLIN]) // only run for these specific relaxing actions
});

What is this magic? How does it work?

Have a read of the Implementing Undo History recipe in the Redux documents, which explains in detail how higher-order reducers work.

License

MIT, see LICENSE.md for more information.