Use formatters from @polkadot/api-format

package.json

@@ -67,6 +67,7 @@
     "sinon-chai": "^2.14.0"
   },
   "dependencies": {
+    "@polkadot/api-format": "^0.2.0",
     "@polkadot/jsonrpc": "^0.2.0",
     "@polkadot/util": "^0.2.0",
     "babel-runtime": "^6.26.0",

src/api.js

@@ -5,10 +5,11 @@ import type { InterfaceDefinition } from '@polkadot/jsonrpc/src/types';
 import type { ApiInterface } from './types';
 import type { ProviderInterface } from './provider/types';
 
+const { formatInputs, formatOutput } = require('@polkadot/api-format');
 const interfaces = require('@polkadot/jsonrpc');
 const { callSignature } = require('@polkadot/jsonrpc/lib/util');
 const { isFunction } = require('@polkadot/util/lib/is');
-const { formatInputs, formatOutput } = require('./format');
+
 const { HttpProvider } = require('./provider');
 
 module.exports = class Api implements ApiInterface {

src/polyfill.spec.js

@@ -0,0 +1,15 @@
+// ISC, Copyright 2017 Jaco Greeff
+
+/* eslint-disable no-unused-expressions */
+
+describe('polyfill', () => {
+  it('adds polyfills with no exceptions', () => {
+    expect(require('./polyfill')).to.be.ok;
+  });
+
+  describe('interfaces', () => {
+    it('fetch is available', () => {
+      expect(fetch).to.be.ok;
+    });
+  });
+});