Update documentation

docs/usage/packers.md

@@ -2,7 +2,48 @@
 
 > Packers are the way in which `docx` turns your code into `.docx` format. It is completely decoupled from the `docx.Document`.
 
-## File System Packer
+## Version 4
+
+Packers in `version 4` and above are now one single `Packer`. It works in both a node and browser environment (Angular etc). Now, the packer returns a `Buffer`, `Blob` or `base64 string`. It is up to you to take that and persist it with node's `fs`, send it down as a downloadable file, or anything else you wish. As of version 4, this library will not have options to export to PDF.
+
+### Export as Buffer
+
+This will return a NodeJS `Buffer`. If this is used in the browser, it will return a `UInt8Array` instead.
+
+```js
+const packer = new docx.Packer();
+
+packer.toBuffer(doc).then((buffer) => {
+    fs.writeFileSync("My Document.docx", buffer);
+});
+```
+
+### Export as a `base64` string
+
+```js
+const packer = new docx.Packer();
+
+packer.toBase64String(doc).then((string) => {
+    console.log(string);
+});
+```
+
+### Export as Blob
+
+This is useful if you want to send it as an downloadable in a browser environment.
+
+```js
+const packer = new docx.Packer();
+
+packer.toBlob(doc).then((blob) => {
+    // saveAs from FileSaver will download the file
+    saveAs(blob, "example.docx");
+});
+```
+
+## Version 3 and below
+
+### File System Packer
 
 ```js
 const docx = require("docx");
@@ -13,7 +54,7 @@ exporter.pack("My Document");
 // Word Document is in file system
 ```
 
-## Buffer Packer
+### Buffer Packer
 
 ```js
 const docx = require("docx");
@@ -23,7 +64,7 @@ const exporter = new docx.BufferPacker(doc);
 const buffer = exporter.pack();
 ```
 
-## Stream Packer
+### Stream Packer
 
 Creates a `node` `Readable` stream
 
@@ -35,7 +76,7 @@ const exporter = new docx.StreamPacker(doc);
 const stream = exporter.pack();
 ```
 
-## Express Packer
+### Express Packer
 
 The old express packer is now deprecated and may disappear soon, so you should upgrade.
 
@@ -56,13 +97,13 @@ const exporter = new docx.StreamPacker(doc);
 const stream = exporter.pack();
 
 // Express' response object
-res.attachment('yourfile.xlsx');
+res.attachment("yourfile.xlsx");
 stream.pipe(res);
 ```
 
 where `res` is the response object obtained through the Express router. It is that simple. The file will begin downloading in the browser.
 
-## PDF Exporting
+### PDF Exporting
 
 You can export your word document as a PDF file like so:
 
@@ -74,7 +115,3 @@ exporter.packPdf("My Document");
 const exporter = new docx.ExpressPacker(doc, res);
 exporter.packPdf("My Document");
 ```
-
-## Browser based docx exporting
-
-It is on the bucket list. It has been requested by a few, and work is already on it