Reduxed Chrome Storage

Redux interface to chrome.storage. Unified way to use Redux in all modern browser extensions. The only way to get Redux working in Manifest V3 Chrome extensions (aside from full reproduction of the Redux code).

Related article

Installation

npm install reduxed-chrome-storage

Usage

Standard way (Promises):

import { createStore } from 'redux';
import storeCreatorFactory from 'reduxed-chrome-storage';
import reducer from './reducer';

const options = {
  createStore: createStore,
  namespace?: ...,
  chromeNs?: ...,
  browserNs?: ...,
  errorListener?: ...,
  storageArea?: ...,
  storageKey?: ...,
  bufferLife?: ...
};
const asyncStoreCreator = storeCreatorFactory(options);
asyncStoreCreator(reducer).then(store => {
  const state = store.getState();
  ...
});

Advanced way (async/await):

...
async () => {
  const asyncStoreCreator = storeCreatorFactory({ createStore });
  const store = await asyncStoreCreator(reducer);
  ...
}
...

One-liner:

...
async () => {
  const store = await storeCreatorFactory({ createStore })( reducer );
  ...
}
...

Storage API errors listening along with size/limits control:

import { createStore } from 'redux';
import storeCreatorFactory from 'reduxed-chrome-storage';
import reducer from './reducer';

const errorListener = (message: string, exceeded: boolean) => {
  ...
};
const options = {
  createStore: createStore,
  errorListener: errorListener,
  namespace?: ...,
  chromeNs?: ...,
  browserNs?: ...,
  storageArea?: ...,
  storageKey?: ...,
  bufferLife?: ...
};
storeCreatorFactory(options)(reducer);

State change listening (special case - only makes sense in Manifest V3 service workers):

import { createStore } from 'redux';
import storeCreatorFactory from 'reduxed-chrome-storage';
import reducer from './reducer';

const changeListener = (store, oldState) => {
  const currentState = store.getState();
  ...
};
const options = {
  createStore: createStore,
  changeListener: changeListener,
  namespace?: ...,
  chromeNs?: ...,
  browserNs?: ...,
  errorListener?: ...,
  storageArea?: ...,
  storageKey?: ...,
  bufferLife?: ...
};
storeCreatorFactory(options)(reducer);

Options

createStore

Type: function

The original Redux's createStore function. The only mandatory option.

namespace

Type: string
Default: 'chrome'

A string to identify the APIs namespace to be used, either 'chrome' or 'browser'. If this and the next two options are missing, the chrome namespace is used by default.

chromeNs

Type: host object (ChromeNamespace in Typescript definition)

The chrome namespace within Manifest V2 extension. If this option is supplied, the previous one is ignored.

browserNs

Type: host object (BrowserNamespace in Typescript definition)

The browser namespace within Firefox extension, or the chrome namespace within Manifest V3 chrome extension. You may pass the chrome namespace within Manifest V3 to make this library use Promise-based APIs under the hood. If this option is supplied, the previous two are ignored.

changeListener

Type: function (ChangeListener in Typescript definition)

A function to be called whenever the state changes, receives two parameters:

1. one-time store - container of the current state;
2. the previous state.

This option only makes sense in Manifest V3 service workers or event-driven background scripts. However it works in the same way in persistent scripts too, which may be useful for cross-browser development. Note: if this option is supplied, the async store creator returned by the factory is not supposed to be immediately used for store creation; its only purpose in this case is to hold the arguments to be passed to the original createStore upon a one-time store creation.

errorListener

Type: function (ErrorListener in Typescript definition)

A function to be called whenever an error occurs during chrome.storage update, receives two parameters:

1. an error message defined by storage API;
2. a boolean indicating if the limit for the used storage area is exceeded.

storageArea

Type: string
Default: 'local'

The name of chrome.storage area to be used, either 'sync' or 'local'. Note: it is not recommended to use sync area for immediately storing the state of extension. Use local area instead - it has less strict limits than sync. If you need to sync the state (entirely or partially) to a user's account, create a temporary store of sync area, then copy the needed data to (or from) the main store (of local area).

storageKey

Type: string
Default: 'reduxed'

Key under which the state will be stored/tracked in chrome.storage.

bufferLife

Type: number
Default: 100

Lifetime of the bulk actions buffer (in ms).

Notes

The usage is the same for any extension component (background or content script or popup - no matter).

asyncStoreCreator function returned by storeCreatorFactory is similar to the original Redux's createStore function except that unlike the latter asyncStoreCreator runs in async way returning a promise instead of a new store (which is due to asynchronous nature of chrome.storage API). asyncStoreCreator has the same syntax as its Redux's counterpart, though its 2nd parameter has a slightly different meaning. Unlike Redux, this library features state persistence through extension's activity periods (browser sessions in the case of persistent extension). With Reduxed Chrome Storage the current state is always persisted in chrome.storage by default. So there is no need to specify a previosly (somewhere) serialized state upon store creation/instantiation. However there may be a need to reset some parts (properties) of the state (e.g. user session variables) to their initial values upon store instantiation. And this is how the 2nd parameter is supposed to be used in Reduxed Chrome Storage: as initial values for some specific state properties. To be more specific, when a new store is created by asyncStoreCreator, first it tries to restore its last state from chrome.storage, then the result is merged with the 2nd parameter (if supplied).

If you're developing a Manifest V3 Chrome extension or a Manifest V2 extension with non-persistent background script, you have to keep in mind that your background script must comply with requirements of event-based model. In the context of usage of this library it means that asyncStoreCreator's promise callback should not contain any extension event listener (e.g. chrome.runtime.onStartup etc). If async/await syntax is used, there should not be any event listener after first await occurrence. Furthermore, storeCreatorFactory should not be called inside any event listener (as it implicitly sets up chrome.storage.onChanged event listener).

License

Licensed under the MIT license.