feat: convert String values to buffers to avoid strange situations in the browser

package.json

@@ -42,11 +42,11 @@
     "multihashes": "^0.3.0"
   },
   "dependencies": {
-    "async": "^2.1.4",
     "multihashing-async": "^0.3.0"
   },
   "engines": {
-    "node": ">=4.0.0"
+    "node": ">=4.0.0",
+    "npm": ">=3.0.0"
   },
   "contributors": [
     "David Dias <daviddias.p@gmail.com>",
@@ -55,4 +55,4 @@
     "greenkeeperio-bot <support@greenkeeper.io>",
     "npmcdn-to-unpkg-bot <npmcdn-to-unpkg-bot@users.noreply.github.com>"
   ]
-}
+}

src/index.js

@@ -15,6 +15,14 @@ function Block (data) {
     throw new Error('Block must be constructed with data')
   }
 
+  if (typeof data !== 'string' || Buffer.isBuffer(data)) {
+    throw new Error('data should be Buffer')
+  }
+
+  if (!Buffer.isBuffer(data)) {
+    data = new Buffer(data)
+  }
+
   this._cache = {}
 
   data = ensureBuffer(data)