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metamask-extension/app/scripts/lib/ComposableObservableStore.js

99 lines
3.0 KiB
JavaScript

import { ObservableStore } from '@metamask/obs-store';
import { getPersistentState } from '@metamask/controllers';
/**
* @typedef {import('@metamask/controllers').ControllerMessenger} ControllerMessenger
*/
/**
* An ObservableStore that can composes a flat
* structure of child stores based on configuration
*/
export default class ComposableObservableStore extends ObservableStore {
/**
* Describes which stores are being composed. The key is the name of the
* store, and the value is either an ObserableStore, or a controller that
* extends one of the two base controllers in the `@metamask/controllers`
* package.
*
* @type {Record<string, object>}
*/
config = {};
/**
* Create a new store
*
* @param {object} options
* @param {object} [options.config] - Map of internal state keys to child stores
* @param {ControllerMessenger} options.controllerMessenger - The controller
* messenger, used for subscribing to events from BaseControllerV2-based
* controllers.
* @param {object} [options.state] - The initial store state
* @param {boolean} [options.persist] - Whether or not to apply the persistence for v2 controllers
*/
constructor({ config, controllerMessenger, state, persist }) {
super(state);
this.persist = persist;
this.controllerMessenger = controllerMessenger;
if (config) {
this.updateStructure(config);
}
}
/**
* Composes a new internal store subscription structure
*
* @param {Record<string, object>} config - Describes which stores are being
* composed. The key is the name of the store, and the value is either an
* ObserableStore, or a controller that extends one of the two base
* controllers in the `@metamask/controllers` package.
*/
updateStructure(config) {
this.config = config;
this.removeAllListeners();
for (const key of Object.keys(config)) {
if (!config[key]) {
throw new Error(`Undefined '${key}'`);
}
const store = config[key];
if (store.subscribe) {
config[key].subscribe((state) => {
this.updateState({ [key]: state });
});
} else {
this.controllerMessenger.subscribe(
`${store.name}:stateChange`,
(state) => {
let updatedState = state;
if (this.persist) {
updatedState = getPersistentState(state, config[key].metadata);
}
this.updateState({ [key]: updatedState });
},
);
}
}
}
/**
* Merges all child store state into a single object rather than
* returning an object keyed by child store class name
*
* @returns {object} Object containing merged child store state
*/
getFlatState() {
if (!this.config) {
return {};
}
let flatState = {};
for (const key of Object.keys(this.config)) {
const controller = this.config[key];
const state = controller.getState
? controller.getState()
: controller.state;
flatState = { ...flatState, ...state };
}
return flatState;
}
}