const ethUtil = require('ethereumjs-util') const assert = require('assert') const BN = require('bn.js') const { ENVIRONMENT_TYPE_POPUP, ENVIRONMENT_TYPE_NOTIFICATION, ENVIRONMENT_TYPE_FULLSCREEN, PLATFORM_FIREFOX, PLATFORM_OPERA, PLATFORM_CHROME, PLATFORM_EDGE, PLATFORM_BRAVE, } = require('./enums') /** * Generates an example stack trace * * @returns {string} A stack trace * */ function getStack () { const stack = new Error('Stack trace generator - not an error').stack return stack } /** * Used to determine the window type through which the app is being viewed. * - 'popup' refers to the extension opened through the browser app icon (in top right corner in chrome and firefox) * - 'responsive' refers to the main browser window * - 'notification' refers to the popup that appears in its own window when taking action outside of metamask * * @returns {string} A single word label that represents the type of window through which the app is being viewed * */ const getEnvironmentType = (url = window.location.href) => { if (url.match(/popup.html(?:#.*)*$/)) { return ENVIRONMENT_TYPE_POPUP } else if (url.match(/home.html(?:\?.+)*$/) || url.match(/home.html(?:#.*)*$/)) { return ENVIRONMENT_TYPE_FULLSCREEN } else { return ENVIRONMENT_TYPE_NOTIFICATION } } /** * Returns the platform (browser) where the extension is running. * * @returns {string} the platform ENUM * */ const getPlatform = _ => { const ua = navigator.userAgent if (ua.search('Firefox') !== -1) { return PLATFORM_FIREFOX } else { if (window && window.chrome && window.chrome.ipcRenderer) { return PLATFORM_BRAVE } else if (ua.search('Edge') !== -1) { return PLATFORM_EDGE } else if (ua.search('OPR') !== -1) { return PLATFORM_OPERA } else { return PLATFORM_CHROME } } } /** * Checks whether a given balance of ETH, represented as a hex string, is sufficient to pay a value plus a gas fee * * @param {object} txParams Contains data about a transaction * @param {string} txParams.gas The gas for a transaction * @param {string} txParams.gasPrice The price per gas for the transaction * @param {string} txParams.value The value of ETH to send * @param {string} hexBalance A balance of ETH represented as a hex string * @returns {boolean} Whether the balance is greater than or equal to the value plus the value of gas times gasPrice * */ function sufficientBalance (txParams, hexBalance) { // validate hexBalance is a hex string assert.equal(typeof hexBalance, 'string', 'sufficientBalance - hexBalance is not a hex string') assert.equal(hexBalance.slice(0, 2), '0x', 'sufficientBalance - hexBalance is not a hex string') const balance = hexToBn(hexBalance) const value = hexToBn(txParams.value) const gasLimit = hexToBn(txParams.gas) const gasPrice = hexToBn(txParams.gasPrice) const maxCost = value.add(gasLimit.mul(gasPrice)) return balance.gte(maxCost) } /** * Converts a BN object to a hex string with a '0x' prefix * * @param {BN} inputBn The BN to convert to a hex string * @returns {string} A '0x' prefixed hex string * */ function bnToHex (inputBn) { return ethUtil.addHexPrefix(inputBn.toString(16)) } /** * Converts a hex string to a BN object * * @param {string} inputHex A number represented as a hex string * @returns {Object} A BN object * */ function hexToBn (inputHex) { return new BN(ethUtil.stripHexPrefix(inputHex), 16) } /** * Used to multiply a BN by a fraction * * @param {BN} targetBN The number to multiply by a fraction * @param {number|string} numerator The numerator of the fraction multiplier * @param {number|string} denominator The denominator of the fraction multiplier * @returns {BN} The product of the multiplication * */ function BnMultiplyByFraction (targetBN, numerator, denominator) { const numBN = new BN(numerator) const denomBN = new BN(denominator) return targetBN.mul(numBN).div(denomBN) } function applyListeners (listeners, emitter) { Object.keys(listeners).forEach((key) => { emitter.on(key, listeners[key]) }) } function removeListeners (listeners, emitter) { Object.keys(listeners).forEach((key) => { emitter.removeListener(key, listeners[key]) }) } module.exports = { removeListeners, applyListeners, getPlatform, getStack, getEnvironmentType, sufficientBalance, hexToBn, bnToHex, BnMultiplyByFraction, }