bugfix default array, generated key, docs (#5)

README.md

@@ -17,13 +17,12 @@ precrypt --html example/index.html --css example/style.css --js example/index.js
 ## Library Usage
 
 ```
-key := precrypt.Render(precrypt.RenderOptions{
+err := precrypt.Render(precrypt.RenderOptions{
     HtmlFiles:  []string{"example/index.html"},
     CssFiles:   []string{"example/style.css"},
     JsFiles:    []string{"example/index.js"},
     Key:        []byte{"passphrasewhichneedstobe32bytes!"},
     Out:        os.Stdout,
-    
 }
 ```
 

cmd/build.go

@@ -46,9 +46,8 @@ var build = &cobra.Command{
 				fmt.Println(err)
 				os.Exit(1)
 			}
-			opts.Key = make([]byte, hex.EncodedLen(len(bytes)))
-			hex.Encode(opts.Key, bytes)
-			fmt.Println(string(opts.Key))
+			opts.Key = bytes
+			fmt.Println(hex.EncodeToString(bytes))
 		}
 		if err := precrypt.Render(opts); err != nil {
 			fmt.Println(err)
@@ -61,7 +60,7 @@ func init() {
 	build.Flags().StringArrayVar(&htmlFiles, "html", []string{}, "--html <file1.html>,<file2.html>")
 	build.Flags().StringArrayVar(&cssFiles, "css", []string{}, "--css <file1.css>,<file2.css>")
 	build.Flags().StringArrayVar(&jsFiles, "js", []string{}, "--js <file1.js>,<file2.js>")
-	build.Flags().StringVar(&key, "key", "", "--key 32byteslong")
+	build.Flags().StringVar(&key, "key", "", "--key hexencoded32bytes")
 }
 
 func Execute() {

pkg/precrypt/precrypt.go

@@ -35,6 +35,7 @@ type RenderOptions struct {
 
 func Render(opts RenderOptions) error {
 	var err error
+
 	if len(opts.Key) != 32 {
 		return errors.New("invalid key length")
 	}
@@ -78,7 +79,7 @@ func Render(opts RenderOptions) error {
 }
 
 func encryptFiles(paths []string, key []byte) ([]string, error) {
-	var ret []string
+	ret := []string{}
 	for _, v := range paths {
 		b, err := encryptFile(v, key)
 		if err != nil {