change isSiadRunning to async isRunning

.babelrc

@@ -1,3 +1,4 @@
 {
-  "presets": ["es2015", "react"]
+  "presets": ["es2015", "stage-3"],
+	"plugins": ["transform-runtime"]
 }

package.json

@@ -8,7 +8,7 @@
   },
   "main": "lib/sia.js",
   "scripts": {
-    "build": "babel --presets es2015,stage-3 -d lib/ src/",
+    "build": "babel -d lib/ src/",
     "test": "npm run lint && mocha --compilers js:babel-register --recursive ./test",
     "prepublish": "npm run build",
     "lint": "eslint --max-warnings 0 ./src ./test",
@@ -32,6 +32,8 @@
   "devDependencies": {
     "babel-cli": "^6.10.1",
     "babel-eslint": "^6.1.2",
+    "babel-plugin-transform-runtime": "^6.9.0",
+    "babel-polyfill": "^6.9.1",
     "babel-preset-es2015": "^6.9.0",
     "babel-preset-react": "^6.11.1",
     "babel-preset-stage-3": "^6.11.0",

src/sia.js

@@ -10,6 +10,9 @@ const hastingsPerSiacoin = new BigNumber('10').toPower(24)
 const siacoinsToHastings = (siacoins) => new BigNumber(siacoins).times(hastingsPerSiacoin)
 const hastingsToSiacoins = (hastings) => new BigNumber(hastings).dividedBy(hastingsPerSiacoin)
 
+// Call makes a call to the Sia API at `address`, with the request options defined by `opts`.
+// returns a promise which resolves with the response if the request completes successfully
+// and rejects with the error if the request fails.
 const call = (address, opts) => new Promise((resolve, reject) => {
 	let callOptions = opts
 	if (typeof opts === 'string') {
@@ -30,8 +33,10 @@ const call = (address, opts) => new Promise((resolve, reject) => {
 		}
 	})
 })
+
 // launch launches a new instance of siad using `settings`.
-// this function can `throw`, callers should catch errors from `spawn`.
+// this function can `throw`, callers should catch errors.
+// callers should also handle the lifecycle of the spawned process.
 const launch = (settings) => {
 	const opts = { }
 	if (process.geteuid) {
@@ -40,17 +45,20 @@ const launch = (settings) => {
 	return spawn(settings.path, [ '--sia-directory=' + settings.datadir ], opts)
 }
 
-// isSiadRunning returns a promise which resolves with true if siad is running at address,
-// or false if siad is not running.
-const isSiadRunning = (address) => new Promise((resolve) => {
-	call(address, '/daemon/version')
-	  .catch(() => resolve(false))
-	  .then(() => resolve(true))
-})
+// isRunning returns true if a successful call can be to /daemon/version
+// using the address provided in `address`.
+async function isRunning(address) {
+	try {
+		await call(address, '/daemon/version')
+		return true
+	} catch (e) {
+		return false
+	}
+}
 
 export {
 	launch,
-	isSiadRunning,
+	isRunning,
 	call,
 	siacoinsToHastings,
 	hastingsToSiacoins,

test/sia.js

@@ -1,7 +1,7 @@
 /* eslint-disable no-unused-expressions */
 import 'babel-polyfill'
 import BigNumber from 'bignumber.js'
-import { siacoinsToHastings, hastingsToSiacoins, isSiadRunning } from '../src/sia.js'
+import { siacoinsToHastings, hastingsToSiacoins, isRunning } from '../src/sia.js'
 import { expect } from 'chai'
 import proxyquire from 'proxyquire'
 import { spy } from 'sinon'
@@ -49,32 +49,20 @@ describe('sia.js wrapper library', () => {
 		})
 	})
 	describe('siad interaction functions', () => {
-		describe('isSiadRunning', () => {
-			it('resolves true when siad is running', (done) => {
+		describe('isRunning', () => {
+			it('returns true when siad is running', async function() {
 				nock('http://localhost:9980')
 				  .get('/daemon/version')
 				  .reply(200, 'test-version')
-
-				isSiadRunning('localhost:9980').then((running) => {
-					if (running) {
-						done()
-					} else {
-						throw new Error('isSiadRunning resolved false when siad was running')
-					}
-				})
+				const running = await isRunning('localhost:9980')
+				expect(running).to.be.true
 			})
-			it('resolves false when siad is not running', (done) => {
+			it('returns false when siad is not running', async function() {
 				nock('http://localhost:9980')
 				  .get('/daemon/version')
 				  .replyWithError('error')
-
-				isSiadRunning('localhost:9980').then((running) => {
-					if (!running) {
-						done()
-					} else {
-						throw new Error('isSiadRunning resolved true when siad was not running')
-					}
-				})
+				const running = await isRunning('localhost:9980')
+				expect(running).to.be.false
 			})
 		})
 		describe('launch', () => {