84 lines
2.2 KiB
JavaScript
84 lines
2.2 KiB
JavaScript
const ObservableStore = require('obs-store')
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const { warn } = require('loglevel')
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// By default, poll every 3 minutes
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const DEFAULT_INTERVAL = 180 * 1000
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/**
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* A controller that polls for token exchange
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* rates based on a user's current token list
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*/
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class TokenRatesController {
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/**
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* Creates a TokenRatesController
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*
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* @param {Object} [config] - Options to configure controller
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*/
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constructor ({ interval = DEFAULT_INTERVAL, preferences } = {}) {
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this.store = new ObservableStore()
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this.preferences = preferences
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this.interval = interval
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}
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/**
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* Updates exchange rates for all tokens
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*/
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async updateExchangeRates () {
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if (!this.isActive) { return }
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const contractExchangeRates = {}
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for (const i in this._tokens) {
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if (this._tokens[i]) {
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const address = this._tokens[i].address
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contractExchangeRates[address] = await this.fetchExchangeRate(address)
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}
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}
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this.store.putState({ contractExchangeRates })
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}
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/**
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* Fetches a token exchange rate by address
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*
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* @param {String} address - Token contract address
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*/
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async fetchExchangeRate (address) {
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try {
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const response = await fetch(`https://metamask.balanc3.net/prices?from=${address}&to=ETH&autoConversion=false&summaryOnly=true`)
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const json = await response.json()
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return json && json.length ? json[0].averagePrice : 0
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} catch (error) {
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warn(`Nifty Wallet - TokenRatesController exchange rate fetch failed for ${address}.`, error)
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return 0
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}
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}
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/**
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* @type {Number}
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*/
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set interval (interval) {
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this._handle && clearInterval(this._handle)
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if (!interval) { return }
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this._handle = setInterval(() => { this.updateExchangeRates() }, interval)
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}
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/**
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* @type {Object}
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*/
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set preferences (preferences) {
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this._preferences && this._preferences.unsubscribe()
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if (!preferences) { return }
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this._preferences = preferences
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this.tokens = preferences.getState().tokens
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preferences.subscribe(({ tokens = [] }) => { this.tokens = tokens })
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}
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/**
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* @type {Array}
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*/
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set tokens (tokens) {
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this._tokens = tokens
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this.updateExchangeRates()
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}
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}
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module.exports = TokenRatesController
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