added additional configuration to editor prompt (#110)

* allow to change the editor behavior

Add two fields `HideDefault` and `AppendDefaul` to `Editor`.

If `HideDefault` is `true`, the default value is not shown
before the launch of the editor. By default this value is `false`.

If `AppendDefault` is `true`, the default value is written to the temporary
file before the launch of the editor and `Prompt()` returns the empty
string if the contents of the temporary file is empty.
By default this value is `false`.

* add tests of HideDefault and AppendDefault to tests/editor.go

editor.go

@@ -26,9 +26,11 @@ Response type is a string.
 */
 type Editor struct {
 	core.Renderer
-	Message string
-	Default string
-	Help    string
+	Message       string
+	Default       string
+	Help          string
+	HideDefault   bool
+	AppendDefault bool
 }
 
 // data available to the templates when processing
@@ -48,7 +50,7 @@ var EditorQuestionTemplate = `
   {{- color "cyan"}}{{.Answer}}{{color "reset"}}{{"\n"}}
 {{- else }}
   {{- if and .Help (not .ShowHelp)}}{{color "cyan"}}[{{ HelpInputRune }} for help]{{color "reset"}} {{end}}
-  {{- if .Default}}{{color "white"}}({{.Default}}) {{color "reset"}}{{end}}
+  {{- if and .Default (not .HideDefault)}}{{color "white"}}({{.Default}}) {{color "reset"}}{{end}}
   {{- color "cyan"}}[Enter to launch editor] {{color "reset"}}
 {{- end}}`
 
@@ -128,6 +130,14 @@ func (e *Editor) Prompt() (interface{}, error) {
 	if _, err := f.Write(bom); err != nil {
 		return "", err
 	}
+
+	// write default value
+	if e.Default != "" && e.AppendDefault {
+		if _, err := f.WriteString(e.Default); err != nil {
+			return "", err
+		}
+	}
+
 	// close the fd to prevent the editor unable to save file
 	if err := f.Close(); err != nil {
 		return "", err
@@ -153,7 +163,7 @@ func (e *Editor) Prompt() (interface{}, error) {
 	text := string(bytes.TrimPrefix(raw, bom))
 
 	// check length, return default value on empty
-	if len(text) == 0 {
+	if len(text) == 0 && !e.AppendDefault {
 		return e.Default, nil
 	}
 

editor_test.go

@@ -33,6 +33,12 @@ func TestEditorRender(t *testing.T) {
 			EditorTemplateData{},
 			"? What is your favorite month: (April) [Enter to launch editor] ",
 		},
+		{
+			"Test Editor question output with HideDefault",
+			Editor{Message: "What is your favorite month:", Default: "April", HideDefault: true},
+			EditorTemplateData{},
+			"? What is your favorite month: [Enter to launch editor] ",
+		},
 		{
 			"Test Editor answer output",
 			Editor{Message: "What is your favorite month:"},

tests/editor.go

@@ -19,6 +19,20 @@ var goodTable = []TestUtil.TestTableEntry{
 			Help:    "Does this work?",
 		}, &answer,
 	},
+	{
+		"should not include the default value in the prompt", &survey.Editor{
+			Message:     "the default value 'Hello World' should not include in the prompt",
+			HideDefault: true,
+			Default:     "Hello World",
+		}, &answer,
+	},
+	{
+		"should write the default value to the temporary file before the launch of the editor", &survey.Editor{
+			Message:       "the default value 'Hello World' is written to the temporary file before the launch of the editor",
+			AppendDefault: true,
+			Default:       "Hello World",
+		}, &answer,
+	},
 }
 
 func main() {