Use NAPI_MODULE_INIT

This allows iltorb to be loaded multiple times during the lifetime of the Node.js process.

Fix #78

src/iltorb.cc

@@ -2,10 +2,8 @@
 #include "dec/stream_decode.h"
 #include "enc/stream_encode.h"
 
-napi_value Init(napi_env env, napi_value exports) {
+NAPI_MODULE_INIT() {
   StreamDecode::Init(env, exports);
   StreamEncode::Init(env, exports);
   return exports;
 }
-
-NAPI_MODULE(NODE_GYP_MODULE_NAME, Init)

test/iltorb.js

@@ -0,0 +1,15 @@
+import test from 'ava';
+
+test('compress an empty buffer', async function(t) {
+  const brotli1 = require('../');
+  const buf1 = await brotli1.compress(Buffer.alloc(0));
+  t.truthy(Buffer.isBuffer(buf1));
+
+  delete require.cache[require.resolve('..')];
+  delete require.cache[require.resolve('../build/bindings/iltorb.node')];
+
+  const brotli2 = require('../');
+  const buf2 = await brotli2.compress(Buffer.alloc(0));
+  t.truthy(Buffer.isBuffer(buf2));
+  t.truthy(Buffer.compare(buf1, buf2) === 0);
+});