Expose error codes (ccxt#60)

Author: bennycode

src/http.js

@@ -21,7 +21,9 @@ const makeQueryString = q =>
 const sendResult = call =>
   call.then(res => Promise.all([res, res.json()])).then(([res, json]) => {
     if (!res.ok) {
-      throw new Error(json.msg || `${res.status} ${res.statusText}`)
+      const error = new Error(json.msg || `${res.status} ${res.statusText}`)
+      error.code = json.code
+      throw error
     }
 
     return json

test/authenticated.js

@@ -128,6 +128,20 @@ test.serial('[REST] tradesHistory', async t => {
   t.is(trades.length, 500)
 })
 
+test.serial('[REST] error code', async t => {
+  try {
+    await client.orderTest({
+      symbol: 'TRXETH',
+      side: 'SELL',
+      type: 'LIMIT',
+      quantity: '-1337.00000000',
+      price: '1.00000000',
+    })
+  } catch (e) {
+    t.is(e.code, -1100)
+  }
+})
+
 test.serial('[WS] user', async t => {
   const clean = await client.ws.user()
   t.truthy(clean)