Typecheck remaining files in src/api

src/api/common/utils.js

@@ -1,17 +1,20 @@
+/* @flow */
 'use strict';
 const BigNumber = require('bignumber.js');
 const core = require('../../core');
 const errors = require('./errors');
 
-function dropsToXrp(drops) {
+type Amount = {currency: string, issuer: string, value: string}
+
+function dropsToXrp(drops: string): string {
   return (new BigNumber(drops)).dividedBy(1000000.0).toString();
 }
 
-function xrpToDrops(xrp) {
+function xrpToDrops(xrp: string): string {
   return (new BigNumber(xrp)).times(1000000.0).floor().toString();
 }
 
-function toRippledAmount(amount) {
+function toRippledAmount(amount: Amount): string|Amount {
   if (amount.currency === 'XRP') {
     return xrpToDrops(amount.value);
   }
@@ -22,7 +25,9 @@ function toRippledAmount(amount) {
   };
 }
 
-function wrapCatch(asyncFunction: () => void): () => void {
+type AsyncFunction = (...x: any) => void
+
+function wrapCatch(asyncFunction: AsyncFunction): AsyncFunction {
   return function() {
     try {
       asyncFunction.apply(this, arguments);
@@ -33,7 +38,10 @@ function wrapCatch(asyncFunction: () => void): () => void {
   };
 }
 
-function composeAsync(wrapper, callback) {
+type Callback = (err: any, data: any) => void
+type Wrapper = (data: any) => any
+
+function composeAsync(wrapper: Wrapper, callback: Callback): Callback {
   return function(error, data) {
     if (error) {
       callback(error);
@@ -50,7 +58,7 @@ function composeAsync(wrapper, callback) {
   };
 }
 
-function convertExceptions(f) {
+function convertExceptions<T>(f: () => T): () => T {
   return function() {
     try {
       return f.apply(this, arguments);