cap maximum uploads due to nginx 128 streams limit

lib/index.js

@@ -7,10 +7,14 @@ import EventEmitter from 'events';
 import { basename, resolve } from 'path';
 import { stat, readFile } from 'fs-promise';
 import resumer from 'resumer';
+import splitArray from 'split-array';
 
 // limit of size of files to find
 const ONEMB = bytes('1mb');
 
+// how many concurrent HTTP/2 stream uploads
+const MAX_CONCURRENT = 10;
+
 export default class Now extends EventEmitter {
   constructor (token, { forceNew = false, debug = false }) {
     super();
@@ -100,7 +104,16 @@ export default class Now extends EventEmitter {
   }
 
   upload () {
-    Promise.all(this._missing.map((sha) => retry(async (bail) => {
+    const parts = splitArray(this._missing, MAX_CONCURRENT);
+
+    if (this._debug) {
+      console.log('> [debug] Will upload ' +
+        `${this._missing.length} files in ${parts.length} ` +
+        `steps of ${MAX_CONCURRENT} uploads.`);
+    }
+
+    const uploadChunk = () => {
+      Promise.all(parts.shift().map((sha) => retry(async (bail) => {
         const file = this._files.get(sha);
         const { data, name } = file;
 
@@ -129,8 +142,11 @@ export default class Now extends EventEmitter {
 
         this.emit('upload', file);
       }, { retries: 5, randomize: true, onRetry: this._onRetry })))
-    .then(() => this.emit('complete'))
+      .then(() => parts.length ? uploadChunk() : this.emit('complete'))
       .catch((err) => this.emit('error', err));
+    };
+
+    uploadChunk();
   }
 
   _onRetry (err) {

package.json

@@ -25,7 +25,8 @@
     "progress": "1.1.8",
     "resumer": "0.0.0",
     "retry": "0.9.0",
-    "spdy": "3.2.3"
+    "spdy": "3.2.3",
+    "split-array": "1.0.1"
   },
   "devDependencies": {
     "alpha-sort": "1.0.2",