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metamask-extension/app/scripts/controllers/token-rates.js
2020-11-02 17:41:28 -06:00

99 lines
2.6 KiB
JavaScript

import ObservableStore from 'obs-store'
import log from 'loglevel'
import { normalize as normalizeAddress } from 'eth-sig-util'
import ethUtil from 'ethereumjs-util'
// By default, poll every 3 minutes
const DEFAULT_INTERVAL = 180 * 1000
/**
* A controller that polls for token exchange
* rates based on a user's current token list
*/
export default class TokenRatesController {
/**
* Creates a TokenRatesController
*
* @param {Object} [config] - Options to configure controller
*/
constructor({ currency, preferences } = {}) {
this.store = new ObservableStore()
this.currency = currency
this.preferences = preferences
}
/**
* Updates exchange rates for all tokens
*/
async updateExchangeRates() {
const contractExchangeRates = {}
const nativeCurrency = this.currency
? this.currency.state.nativeCurrency.toLowerCase()
: 'eth'
const pairs = this._tokens.map((token) => token.address).join(',')
const query = `contract_addresses=${pairs}&vs_currencies=${nativeCurrency}`
if (this._tokens.length > 0) {
try {
const response = await window.fetch(
`https://api.coingecko.com/api/v3/simple/token_price/ethereum?${query}`,
)
const prices = await response.json()
this._tokens.forEach((token) => {
const price =
prices[token.address.toLowerCase()] ||
prices[ethUtil.toChecksumAddress(token.address)]
contractExchangeRates[normalizeAddress(token.address)] = price
? price[nativeCurrency]
: 0
})
} catch (error) {
log.warn(
`MetaMask - TokenRatesController exchange rate fetch failed.`,
error,
)
}
}
this.store.putState({ contractExchangeRates })
}
/* eslint-disable accessor-pairs */
/**
* @type {Object}
*/
set preferences(preferences) {
this._preferences && this._preferences.unsubscribe()
if (!preferences) {
return
}
this._preferences = preferences
this.tokens = preferences.getState().tokens
preferences.subscribe(({ tokens = [] }) => {
this.tokens = tokens
})
}
/**
* @type {Array}
*/
set tokens(tokens) {
this._tokens = tokens
this.updateExchangeRates()
}
/* eslint-enable accessor-pairs */
start(interval = DEFAULT_INTERVAL) {
this._handle && clearInterval(this._handle)
if (!interval) {
return
}
this._handle = setInterval(() => {
this.updateExchangeRates()
}, interval)
this.updateExchangeRates()
}
stop() {
this._handle && clearInterval(this._handle)
}
}