refactor(prompt): revert clear behavior (#119)

prompt/_generic_input.ts

@@ -70,7 +70,6 @@ export abstract class GenericInput<T, S extends GenericInputPromptSettings<T>>
 
     message += underline(this.input);
 
-    this.clear();
     this.write(message);
 
     this.screen.cursorTo(length + this.index + 1);

prompt/_generic_list.ts

@@ -68,7 +68,6 @@ export abstract class GenericList<T, V, S extends GenericListSettings<T, V>>
    * @param message Prompt message.
    */
   protected render(message: string): void {
-    this.clear();
     this.writeLine(message);
     this.writeListItems();
   }

prompt/_generic_prompt.ts

@@ -47,6 +47,7 @@ export abstract class GenericPrompt<
 
   protected screen = AnsiEscape.from(Deno.stdout);
   protected lastError: string | undefined;
+  protected isRunning = false;
   protected value: T | undefined;
 
   /**
@@ -105,14 +106,19 @@ export abstract class GenericPrompt<
   protected abstract getValue(): V;
 
   /** Clear prompt output. */
-  protected clear() {
+  protected clear(): void {
     this.screen
       .cursorLeft()
       .eraseDown();
   }
 
   /** Execute the prompt. */
   protected async execute(): Promise<T> {
+    if (this.lastError || this.isRunning) {
+      this.clear();
+    }
+    this.isRunning = true;
+
     const message: string = await this.getMessage();
     // be sure there are empty lines after the cursor to fix restoring the
     // cursor if terminal output is longer than terminal window.
@@ -146,6 +152,7 @@ export abstract class GenericPrompt<
     this.screen.cursorShow();
 
     GenericPrompt.injectedValue = undefined;
+    this.isRunning = false;
 
     return this.value;
   }

prompt/list.ts

@@ -67,7 +67,6 @@ export class List extends GenericInput<string[], ListSettings> {
     this.input = oldInputParts.join(separator);
     this.index -= oldInput.length - this.input.length;
 
-    this.clear();
     this.write(message);
 
     this.screen.cursorTo(length - 1 + this.index);

prompt/secret.ts

@@ -61,7 +61,6 @@ export class Secret extends GenericInput<string, SecretSettings> {
 
     message += underline(secret);
 
-    this.clear();
     this.write(message);
 
     this.screen.cursorTo(length - 1 + this.index);

prompt/toggle.ts

@@ -76,7 +76,6 @@ export class Toggle extends GenericPrompt<boolean, string, ToggleSettings> {
       message += dim(this.settings.inactive + " / " + this.settings.active);
     }
 
-    this.clear();
     this.write(message);
   }