From faa9cbd29d0fe89c5919d20c81c64660a04eb6ac Mon Sep 17 00:00:00 2001
From: Pooya Parsa <pooya@pi0.io>
Date: Fri, 20 Dec 2024 00:41:35 +0100
Subject: [PATCH] feat(prompt): configurable cancel strategy (#325)

---
 README.md     | 10 ++++++-
 src/prompt.ts | 82 +++++++++++++++++++++++++++++++++++++++++++++------
 2 files changed, 82 insertions(+), 10 deletions(-)

diff --git a/README.md b/README.md
index fcd86c2..762208a 100644
--- a/README.md
+++ b/README.md
@@ -82,10 +82,18 @@ Log to all reporters.
 
 Example: `consola.info('Message')`
 
-#### `await prompt(message, { type })`
+#### `await prompt(message, { type, cancel })`
 
 Show an input prompt. Type can either of `text`, `confirm`, `select` or `multiselect`.
 
+If prompt is canceled by user (with Ctrol+C), default value will be resolved by default. This strategy can be configured by setting `{ cancel: "..." }` option:
+
+- `"default"` - Resolve the promise with the `default` value or `initial` value.
+- `"undefined`" - Resolve the promise with `undefined`.
+- `"null"` - Resolve the promise with `null`.
+- `"symbol"` - Resolve the promise with a symbol `Symbol.for("cancel")`.
+- `"reject"` - Reject the promise with an error.
+
 See [examples/prompt.ts](./examples/prompt.ts) for usage examples.
 
 #### `addReporter(reporter)`
diff --git a/src/prompt.ts b/src/prompt.ts
index fc8d857..e24f21f 100644
--- a/src/prompt.ts
+++ b/src/prompt.ts
@@ -6,7 +6,24 @@ type SelectOption = {
   hint?: string;
 };
 
-export type TextPromptOptions = {
+export const kCancel = Symbol.for("cancel");
+
+export type PromptCommonOptions = {
+  /**
+   * Specify how to handle a cancelled prompt (e.g. by pressing Ctrl+C).
+   *
+   * Default strategy is `"default"`.
+   *
+   * - `"default"` - Resolve the promise with the `default` value or `initial` value.
+   * - `"undefined`" - Resolve the promise with `undefined`.
+   * - `"null"` - Resolve the promise with `null`.
+   * - `"symbol"` - Resolve the promise with a symbol `Symbol.for("cancel")`.
+   * - `"reject"`  - Reject the promise with an error.
+   */
+  cancel?: "reject" | "default" | "undefined" | "null" | "symbol";
+};
+
+export type TextPromptOptions = PromptCommonOptions & {
   /**
    * Specifies the prompt type as text.
    * @optional
@@ -33,7 +50,7 @@ export type TextPromptOptions = {
   initial?: string;
 };
 
-export type ConfirmPromptOptions = {
+export type ConfirmPromptOptions = PromptCommonOptions & {
   /**
    * Specifies the prompt type as confirm.
    */
@@ -46,7 +63,7 @@ export type ConfirmPromptOptions = {
   initial?: boolean;
 };
 
-export type SelectPromptOptions = {
+export type SelectPromptOptions = PromptCommonOptions & {
   /**
    * Specifies the prompt type as select.
    */
@@ -64,7 +81,7 @@ export type SelectPromptOptions = {
   options: (string | SelectOption)[];
 };
 
-export type MultiSelectOptions = {
+export type MultiSelectOptions = PromptCommonOptions & {
   /**
    * Specifies the prompt type as multiselect.
    */
@@ -108,6 +125,20 @@ type inferPromptReturnType<T extends PromptOptions> =
           ? T["options"]
           : unknown;
 
+type inferPromptCancalReturnType<T extends PromptOptions> = T extends {
+  cancel: "reject";
+}
+  ? never
+  : T extends { cancel: "default" }
+    ? inferPromptReturnType<T>
+    : T extends { cancel: "undefined" }
+      ? undefined
+      : T extends { cancel: "null" }
+        ? null
+        : T extends { cancel: "symbol" }
+          ? typeof kCancel
+          : inferPromptReturnType<T> /* default */;
+
 /**
  * Asynchronously prompts the user for input based on specified options.
  * Supports text, confirm, select and multi-select prompts.
@@ -123,21 +154,54 @@ export async function prompt<
 >(
   message: string,
   opts: PromptOptions = {},
-): Promise<inferPromptReturnType<T>> {
+): Promise<inferPromptReturnType<T> | inferPromptCancalReturnType<T>> {
+  const handleCancel = (value: unknown) => {
+    if (
+      typeof value !== "symbol" ||
+      value.toString() !== "Symbol(clack:cancel)"
+    ) {
+      return value;
+    }
+
+    switch (opts.cancel) {
+      case "reject": {
+        const error = new Error("Prompt cancelled.");
+        error.name = "ConsolaPromptCancelledError";
+        if (Error.captureStackTrace) {
+          Error.captureStackTrace(error, prompt);
+        }
+        throw error;
+      }
+      case "undefined": {
+        return undefined;
+      }
+      case "null": {
+        return null;
+      }
+      case "symbol": {
+        return kCancel;
+      }
+      default:
+      case "default": {
+        return (opts as TextPromptOptions).default ?? opts.initial;
+      }
+    }
+  };
+
   if (!opts.type || opts.type === "text") {
     return (await text({
       message,
       defaultValue: opts.default,
       placeholder: opts.placeholder,
       initialValue: opts.initial as string,
-    })) as any;
+    }).then(handleCancel)) as any;
   }
 
   if (opts.type === "confirm") {
     return (await confirm({
       message,
       initialValue: opts.initial,
-    })) as any;
+    }).then(handleCancel)) as any;
   }
 
   if (opts.type === "select") {
@@ -147,7 +211,7 @@ export async function prompt<
         typeof o === "string" ? { value: o, label: o } : o,
       ),
       initialValue: opts.initial,
-    })) as any;
+    }).then(handleCancel)) as any;
   }
 
   if (opts.type === "multiselect") {
@@ -158,7 +222,7 @@ export async function prompt<
       ),
       required: opts.required,
       initialValues: opts.initial,
-    })) as any;
+    }).then(handleCancel)) as any;
   }
 
   throw new Error(`Unknown prompt type: ${opts.type}`);