Convert from Flow to Typescript (#816)

* convert to typescript
* add docs for custom node typing
* update webpack, gulpfile

src/ledger/accountinfo.ts

@@ -0,0 +1,62 @@
+import {validate, removeUndefined, dropsToXrp} from '../common'
+
+type AccountData = {
+  Sequence: number,
+  Account: string,
+  Balance: string,
+  Flags: number,
+  LedgerEntryType: string,
+  OwnerCount: number,
+  PreviousTxnID: string,
+  AccountTxnID?: string,
+  PreviousTxnLgrSeq: number,
+  index: string
+}
+
+type AccountDataResponse = {
+  account_data: AccountData,
+  ledger_current_index?: number,
+  ledger_hash?: string,
+  ledger_index: number,
+  validated: boolean
+}
+
+type AccountInfoOptions = {
+  ledgerVersion?: number
+}
+
+type AccountInfoResponse = {
+  sequence: number,
+  xrpBalance: string,
+  ownerCount: number,
+  previousInitiatedTransactionID: string,
+  previousAffectingTransactionID: string,
+  previousAffectingTransactionLedgerVersion: number
+}
+
+function formatAccountInfo(response: AccountDataResponse) {
+  const data = response.account_data
+  return removeUndefined({
+    sequence: data.Sequence,
+    xrpBalance: dropsToXrp(data.Balance),
+    ownerCount: data.OwnerCount,
+    previousInitiatedTransactionID: data.AccountTxnID,
+    previousAffectingTransactionID: data.PreviousTxnID,
+    previousAffectingTransactionLedgerVersion: data.PreviousTxnLgrSeq
+  })
+}
+
+function getAccountInfo(address: string, options: AccountInfoOptions = {}
+): Promise<AccountInfoResponse> {
+  validate.getAccountInfo({address, options})
+
+  const request = {
+    command: 'account_info',
+    account: address,
+    ledger_index: options.ledgerVersion || 'validated'
+  }
+
+  return this.connection.request(request).then(formatAccountInfo)
+}
+
+export default getAccountInfo