@metamask/assets-controllers

@metamask/assets-controllers

Controllers which manage interactions involving ERC-20, ERC-721, and ERC-1155 tokens (including NFTs).

Installation

yarn add @metamask/assets-controllers

or

npm install @metamask/assets-controllers

Controllers

This package features the following controllers:

• AccountTrackerController keeps a updated list of the accounts in the currently selected keychain which is updated automatically on a schedule or on demand.
• AssetsContractController provides a set of convenience methods that use contracts to retrieve information about tokens, read token balances, and transfer tokens.
• CollectibleDetectionController keeps a periodically updated list of ERC-721 tokens assigned to the currently selected address.
• CollectiblesController tracks ERC-721 and ERC-1155 tokens assigned to the currently selected address, using OpenSea to retrieve token information.
• CurrencyRateController keeps a periodically updated value of the exchange rate from the currently selected "native" currency to another (handling testnet tokens specially).
• DeFiPositionsController keeps a periodically updated value of the DeFi positions for the owner EVM addresses.
• RatesController keeps a periodically updated value for the exchange rates for different cryptocurrencies. The difference between the RatesController and CurrencyRateController is that the second one is coupled to the NetworksController and is EVM specific, whilst the first one can handle different blockchain currencies like BTC and SOL.
• TokenBalancesController keeps a periodically updated set of balances for the current set of ERC-20 tokens. It supports real-time balance updates via WebSocket and intelligent polling management. See Real-Time Balance Updates Flow for details.
• TokenDetectionController keeps a periodically updated list of ERC-20 tokens assigned to the currently selected address.
• TokenListController uses the MetaSwap API to keep a periodically updated list of known ERC-20 tokens along with their metadata.
• TokenRatesController keeps a periodically updated list of exchange rates for known ERC-20 tokens relative to the currently selected native currency.
• TokensController stores the ERC-20 and ERC-721 tokens, along with their metadata, that are listed in the wallet under the currently selected address on the currently selected chain.

RatesController

The RatesController is responsible for managing the state related to cryptocurrency exchange rates and periodically updating these rates by fetching new data from an external API.

// Initialize the RatesController
const ratesController = new RatesController({
  interval: 180000,
  includeUsdRate: true,
  state: {
    fiatCurrency: 'eur',
    cryptocurrencies: [Cryptocurrency.Btc],
  },
});

// Start the polling process
ratesController.start().then(() => {
  console.log('Polling for exchange rates has started.');
});

// Stop the polling process after some time
setTimeout(() => {
  ratesController.stop().then(() => {
    console.log('Polling for exchange rates has stopped.');
  });
}, 300000);

Contributing

This package is part of a monorepo. Instructions for contributing can be found in the monorepo README.