Merge pull request #36 from decentraland/feature/new-tx-utils

feat: New txUtils object for handling transactions

src/ethereum/eth.js

@@ -31,7 +31,7 @@ export const eth = {
    * @return {boolean} - True if the connection was successful
    */
   async connect(options = {}) {
-    if (this.wallet && this.wallet.isConnected()) {
+    if (this.isConnected()) {
       this.disconnect()
     }
 
@@ -64,6 +64,10 @@ export const eth = {
     return wallet
   },
 
+  isConnected() {
+    return (this.wallet && this.wallet.isConnected()) || !!web3
+  },
+
   disconnect() {
     if (this.wallet) {
       this.wallet.disconnect()

src/ethereum/index.js

@@ -1,4 +1,4 @@
 export { eth } from './eth'
 export { Contract } from './Contract'
 export { SignedMessage } from './SignedMessage'
-export { tx } from './tx'
+export { txUtils } from './txUtils'

src/ethereum/txUtils.js

@@ -0,0 +1,120 @@
+import { Log } from '../log'
+import { sleep } from '../utils'
+import { eth } from './eth'
+
+const log = new Log('txUtils')
+
+/**
+ * Some utility functions to work with Ethereum transactions.
+ * @namespace
+ */
+export const txUtils = {
+  DUMMY_TX_ID: '0xdeadbeef',
+
+  TRANSACTION_FETCH_DELAY: 10 * 1000,
+
+  TRANSACTION_STATUS: Object.freeze({
+    pending: 'pending',
+    confirmed: 'confirmed',
+    failed: 'failed'
+  }),
+
+  /**
+   * Waits until the transaction finishes. Returns if it was successfull.
+   * Throws if the transaction fails or if it lacks any of the supplied events
+   * @param  {string} txId - Transaction id to watch
+   * @param  {Array<string>|string} events - Events to watch. See {@link txUtils#getLogEvents}
+   * @return {object} data - Current transaction data. See {@link txUtils#getTransaction}
+   */
+  async getConfirmedTransaction(txId, events) {
+    const tx = await txUtils.waitForCompletion(txId)
+
+    if (this.isFailure(tx)) {
+      throw new Error(`Transaction "${txId}" failed`)
+    }
+
+    if (!this.hasLogEvents(tx, events)) {
+      throw new Error(`Missing events for transaction "${txId}": ${events}`)
+    }
+
+    return tx
+  },
+
+  /**
+   * Wait until a transaction finishes by either being mined or failing
+   * @param  {string} txId - Transaction id to watch
+   * @return {object} data - Current transaction data. See {@link txUtils#getTransaction}
+   */
+  async waitForCompletion(txId) {
+    const tx = await this.getTransaction(txId)
+
+    if (this.isPending(tx) || !tx.recepeit) {
+      log.debug(`"${txId}" pending, wait ${this.TRANSACTION_FETCH_DELAY}ms`)
+      await sleep(this.TRANSACTION_FETCH_DELAY)
+      return this.waitForCompletion(txId)
+    }
+
+    log.debug(`"${txId}" completed`)
+    return tx
+  },
+
+  /**
+   * Get the transaction status and recepeit
+   * @param  {string} txId - Transaction id
+   * @return {object} data - Current transaction data. See {@link https://github.com/ethereum/wiki/wiki/JavaScript-API#web3ethgettransaction}
+   * @return {object.recepeit} transaction - Transaction recepeit
+   */
+  async getTransaction(txId) {
+    const [tx, recepeit] = await Promise.all([
+      eth.fetchTxStatus(txId),
+      eth.fetchTxReceipt(txId)
+    ])
+
+    return { ...tx, recepeit }
+  },
+
+  /**
+   * Expects the result of getTransaction's geth command and returns true if the transaction is still pending.
+   * It'll also check for a pending status prop against {@link txUtils#TRANSACTION_STATUS}
+   * @param {object} tx - The transaction object
+   * @return boolean
+   */
+  isPending(tx) {
+    return (
+      tx &&
+      (tx.blockNumber === null || tx.status === this.TRANSACTION_STATUS.pending)
+    )
+  },
+
+  /**
+   * Expects the result of getTransactionRecepeit's geth command and returns true if the transaction failed.
+   * It'll also check for a failed status prop against {@link txUtils#TRANSACTION_STATUS}
+   * @param {object} tx - The transaction object
+   * @return boolean
+   */
+  isFailure(tx) {
+    return (
+      tx &&
+      (!tx.recepeit ||
+        tx.recepeit.status === '0x0' ||
+        tx.status === this.TRANSACTION_STATUS.failed)
+    )
+  },
+
+  /**
+   * Returns true if a transaction contains an event
+   * @param {Array<object>} tx - Transaction with a decoded recepeit
+   * @param {Array<string>|string} eventNames - A string or array of strings with event names you want to search for
+   * @return boolean
+   */
+  hasLogEvents(tx, eventNames) {
+    if (!eventNames || eventNames.length === 0) return true
+    if (!tx.recepit) return false
+
+    if (!Array.isArray(eventNames)) eventNames = [eventNames]
+
+    return tx.recepeit
+      .filter(log => log && log.name)
+      .every(log => eventNames.includes(log.name))
+  }
+}