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metamask-extension/app/scripts/controllers/cached-balances.js
Erik Marks 76a2a9bb8b
@metamask/eslint config@5.0.0 (#10358)
* @metamask/eslint-config@5.0.0
* Update eslintrc and prettierrc
* yarn lint:fix
2021-02-04 10:15:23 -08:00

90 lines
2.5 KiB
JavaScript

import { ObservableStore } from '@metamask/obs-store';
/**
* @typedef {Object} CachedBalancesOptions
* @property {Object} accountTracker An {@code AccountTracker} reference
* @property {Function} getNetwork A function to get the current network
* @property {Object} initState The initial controller state
*/
/**
* Background controller responsible for maintaining
* a cache of account balances in local storage
*/
export default class CachedBalancesController {
/**
* Creates a new controller instance
*
* @param {CachedBalancesOptions} [opts] - Controller configuration parameters
*/
constructor(opts = {}) {
const { accountTracker, getNetwork } = opts;
this.accountTracker = accountTracker;
this.getNetwork = getNetwork;
const initState = { cachedBalances: {}, ...opts.initState };
this.store = new ObservableStore(initState);
this._registerUpdates();
}
/**
* Updates the cachedBalances property for the current network. Cached balances will be updated to those in the passed accounts
* if balances in the passed accounts are truthy.
*
* @param {Object} obj - The the recently updated accounts object for the current network
* @returns {Promise<void>}
*/
async updateCachedBalances({ accounts }) {
const network = await this.getNetwork();
const balancesToCache = await this._generateBalancesToCache(
accounts,
network,
);
this.store.updateState({
cachedBalances: balancesToCache,
});
}
_generateBalancesToCache(newAccounts, currentNetwork) {
const { cachedBalances } = this.store.getState();
const currentNetworkBalancesToCache = { ...cachedBalances[currentNetwork] };
Object.keys(newAccounts).forEach((accountID) => {
const account = newAccounts[accountID];
if (account.balance) {
currentNetworkBalancesToCache[accountID] = account.balance;
}
});
const balancesToCache = {
...cachedBalances,
[currentNetwork]: currentNetworkBalancesToCache,
};
return balancesToCache;
}
/**
* Removes cachedBalances
*/
clearCachedBalances() {
this.store.updateState({ cachedBalances: {} });
}
/**
* Sets up listeners and subscriptions which should trigger an update of cached balances. These updates will
* happen when the current account changes. Which happens on block updates, as well as on network and account
* selections.
*
* @private
*
*/
_registerUpdates() {
const update = this.updateCachedBalances.bind(this);
this.accountTracker.store.subscribe(update);
}
}