diff --git a/package.json b/package.json
index f6582ddd6..e833d7381 100644
--- a/package.json
+++ b/package.json
@@ -40,10 +40,10 @@
     "babel-plugin-istanbul": "^4.1.5",
     "babel-preset-env": "^1.6.1",
     "babel-register": "^6.16.3",
-    "chai": "^3.5.0",
+    "chai": "^4.2.0",
     "chai-as-promised": "^7.1.1",
-    "chai-iterator": "^1.1.1",
-    "chai-string": "^1.3.0",
+    "chai-iterator": "^3.0.2",
+    "chai-string": "^1.5.0",
     "codecov": "^3.0.0",
     "cross-env": "^5.1.3",
     "form-data": "^2.3.1",
@@ -61,10 +61,10 @@
   },
   "dependencies": {
     "@mattiasbuelens/web-streams-polyfill": "^0.3.2",
-    "busboy": "^0.3.0",
-    "formdata-node": "^1.5.1"
+    "busboy": "^0.3.1",
+    "formdata-node": "^2.4.0"
   },
   "peerDependencies": {
-    "form-data": ">= 2.1.0"
+    "form-data": ">=3.0.0"
   }
 }
diff --git a/src/blob.js b/src/blob.js
index b5fa64565..b4b867abc 100644
--- a/src/blob.js
+++ b/src/blob.js
@@ -1,8 +1,10 @@
 // Based on https://github.com/tmpvar/jsdom/blob/aa85b2abf07766ff7bf5c1f6daafb3726f2f2db5/lib/jsdom/living/blob.js
 // (MIT licensed)
+import { TextDecoder } from 'util'
 
 export const BUFFER = Symbol('buffer');
 const TYPE = Symbol('type');
+const decoder = new TextDecoder('utf-8')
 
 export default class Blob {
 	constructor() {
@@ -41,43 +43,31 @@ export default class Blob {
 			this[TYPE] = type;
 		}
 	}
-	get size() {
+	get size () {
 		return this[BUFFER].length;
 	}
-	get type() {
+	get type () {
 		return this[TYPE];
 	}
-	slice() {
+	arrayBuffer (start = 0, end) {
 		const size = this.size;
 
-		const start = arguments[0];
-		const end = arguments[1];
-		let relativeStart, relativeEnd;
-		if (start === undefined) {
-			relativeStart = 0;
-		} else if (start < 0) {
-			relativeStart = Math.max(size + start, 0);
-		} else {
-			relativeStart = Math.min(start, size);
-		}
-		if (end === undefined) {
-			relativeEnd = size;
-		} else if (end < 0) {
-			relativeEnd = Math.max(size + end, 0);
-		} else {
-			relativeEnd = Math.min(end, size);
-		}
-		const span = Math.max(relativeEnd - relativeStart, 0);
+		start = start < 0 ? Math.max(size + start, 0) : (start !== 0 ? Math.min(start, size) : start)
+		end = !end ? size : (size < 0 ? Math.max(size + end, 0) : Math.min(end, size))
 
-		const buffer = this[BUFFER];
-		const slicedBuffer = buffer.slice(
-			relativeStart,
-			relativeStart + span
-		);
+		const span = Math.max(end - start)
+		const buffer = this[BUFFER]
+		return buffer.slice(start, start + span)
+	}
+	slice () {
+		const slicedBuffer = this.arrayBuffer(...arguments)
 		const blob = new Blob([], { type: arguments[2] });
 		blob[BUFFER] = slicedBuffer;
 		return blob;
 	}
+	text () {
+		return decoder.decode(this[BUFFER]).toString()
+	}
 }
 
 Object.defineProperties(Blob.prototype, {