fix: generics & inferences (#153)

Author: fraxken

README.md

@@ -94,7 +94,7 @@ const name = await question("What's your name ?", {
 ### `select()`
 
 ```ts
-select(message: string, options: SelectOptions): Promise<string>
+select<T extends string>(message: string, options: SelectOptions<T>): Promise<T>
 ```
 
 Scrollable select depending `maxVisible` (default `8`).
@@ -114,7 +114,7 @@ Use `options.skip` to skip prompt. It will return the first choice.
 ### `multiselect()`
 
 ```ts
-multiselect(message: string, options: MultiselectOptions): Promise<[string]>
+multiselect<T extends string>(message: string, options: MultiselectOptions<T>): Promise<T[]>
 ```
 
 Scrollable multiselect depending `options.maxVisible` (default `8`).<br>
@@ -196,46 +196,46 @@ export interface AbstractPromptOptions {
   stdin?: Stdin;
   stdout?: Stdout;
   message: string;
-  sginal?: AbortSignal;
+  skip?: boolean;
+  signal?: AbortSignal;
 }
 
-export interface PromptValidator<T = string | string[] | boolean> {
-    validate: (input: T) => boolean;
-    error: (input: T) => string;
+export interface PromptValidator<T extends string | string[]> {
+  validate: (input: T) => boolean;
 }
 
 export interface QuestionOptions extends SharedOptions {
   defaultValue?: string;
-  validators?: Validator[];
+  validators?: PromptValidator<string>[];
   secure?: boolean;
 }
 
-export interface Choice {
-  value: any;
+export interface Choice<T = any> {
+  value: T;
   label: string;
   description?: string;
 }
 
-export interface SelectOptions extends SharedOptions  {
-  choices: (Choice | string)[];
+export interface SelectOptions<T extends string> extends AbstractPromptOptions {
+  choices: (Choice<T> | T)[];
   maxVisible?: number;
-  ignoreValues?: (string | number | boolean)[];
-  validators?: Validator[];
+  ignoreValues?: (T | number | boolean)[];
+  validators?: PromptValidator<string>[];
   autocomplete?: boolean;
   caseSensitive?: boolean;
 }
 
-export interface MultiselectOptions extends SharedOptions  {
-  choices: (Choice | string)[];
+export interface MultiselectOptions<T extends string> extends AbstractPromptOptions {
+  choices: (Choice<T> | T)[];
   maxVisible?: number;
-  preSelectedChoices?: (Choice | string)[];
-  validators?: Validator[];
+  preSelectedChoices?: (Choice<T> | T)[];
+  validators?: PromptValidator<string[]>[];
   autocomplete?: boolean;
   caseSensitive?: boolean;
   showHint?: boolean;
 }
 
-export interface ConfirmOptions extends SharedOptions  {
+export interface ConfirmOptions extends AbstractPromptOptions {
   initial?: boolean;
 }
 ```

package.json

@@ -5,8 +5,9 @@
   "scripts": {
     "build": "tsup index.ts --format cjs,esm --dts --clean",
     "prepublishOnly": "npm run build",
-    "test": "glob -c \"tsx --test\" \"./test/**/*.test.ts\"",
-    "coverage": "c8 -r html npm run test",
+    "test-only": "glob -c \"tsx --test\" \"./test/**/*.test.ts\"",
+    "test-types": "npm run build && tsd",
+    "test": "c8 -r html npm run test-only && npm run test-types",
     "lint": "eslint src test",
     "lint:fix": "eslint . --fix"
   },
@@ -36,6 +37,7 @@
     "@types/node": "^24.0.3",
     "c8": "^10.1.3",
     "glob": "^11.0.0",
+    "tsd": "^0.33.0",
     "tsup": "^8.3.5",
     "tsx": "^4.19.2",
     "typescript": "^5.7.2"
@@ -46,5 +48,8 @@
   "bugs": {
     "url": "https://github.com/TopCli/prompts/issues"
   },
-  "homepage": "https://github.com/TopCli/prompts#readme"
+  "homepage": "https://github.com/TopCli/prompts#readme",
+  "tsd": {
+    "directory": "test/types"
+  }
 }

src/prompts/abstract.ts

@@ -30,7 +30,7 @@ export interface AbstractPromptOptions {
   signal?: AbortSignal;
 }
 
-export class AbstractPrompt<T> extends EventEmitter {
+export class AbstractPrompt<T extends string | boolean> extends EventEmitter {
   stdin: Stdin;
   stdout: Stdout;
   message: string;

src/prompts/multiselect.ts

@@ -15,8 +15,8 @@ const kRequiredChoiceProperties = ["label", "value"];
 export interface MultiselectOptions<T extends string> extends AbstractPromptOptions {
   choices: (Choice<T> | T)[];
   maxVisible?: number;
-  preSelectedChoices?: (Choice | T)[];
-  validators?: PromptValidator<T[]>[];
+  preSelectedChoices?: (Choice<T> | T)[];
+  validators?: PromptValidator<string[]>[];
   autocomplete?: boolean;
   caseSensitive?: boolean;
   showHint?: boolean;
@@ -27,7 +27,7 @@ type VoidFn = () => void;
 export class MultiselectPrompt<T extends string> extends AbstractPrompt<T> {
   #boundExitEvent: VoidFn = () => void 0;
   #boundKeyPressEvent: VoidFn = () => void 0;
-  #validators: PromptValidator<T[]>[];
+  #validators: PromptValidator<string[]>[];
   #showHint: boolean;
 
   activeIndex = 0;
@@ -52,7 +52,11 @@ export class MultiselectPrompt<T extends string> extends AbstractPrompt<T> {
     return this.choices.filter((choice) => this.#filterChoice(choice, autocompleteValue, isCaseSensitive));
   }
 
-  #filterChoice(choice: T | Choice | string, autocompleteValue: string, isCaseSensitive = false) {
+  #filterChoice(
+    choice: T | Choice<T> | string,
+    autocompleteValue: string,
+    isCaseSensitive = false
+  ) {
     // eslint-disable-next-line no-nested-ternary
     const choiceValue = typeof choice === "string" ?
       (isCaseSensitive ? choice : choice.toLowerCase()) :

src/prompts/question.ts

@@ -10,7 +10,7 @@ import { isValid, type PromptValidator, resultError } from "../validators.js";
 
 export interface QuestionOptions extends AbstractPromptOptions {
   defaultValue?: string;
-  validators?: PromptValidator[];
+  validators?: PromptValidator<string>[];
   secure?: boolean | {
     placeholder: string;
   };
@@ -22,7 +22,7 @@ export class QuestionPrompt extends AbstractPrompt<string> {
   questionSuffixError: string;
   answer?: string;
   answerBuffer?: Promise<string>;
-  #validators: PromptValidator[];
+  #validators: PromptValidator<string>[];
   #secure: boolean;
   #securePlaceholder: string | null = null;
 

src/prompts/select.ts

@@ -16,17 +16,17 @@ export interface SelectOptions<T extends string> extends AbstractPromptOptions {
   choices: (Choice<T> | T)[];
   maxVisible?: number;
   ignoreValues?: (T | number | boolean)[];
-  validators?: PromptValidator<T>[];
+  validators?: PromptValidator<string>[];
   autocomplete?: boolean;
   caseSensitive?: boolean;
 }
 
 type VoidFn = () => void;
 
-export class SelectPrompt<T extends string = string> extends AbstractPrompt<T> {
+export class SelectPrompt<T extends string> extends AbstractPrompt<T> {
   #boundExitEvent: VoidFn = () => void 0;
   #boundKeyPressEvent: VoidFn = () => void 0;
-  #validators: PromptValidator<T>[];
+  #validators: PromptValidator<string>[];
   activeIndex = 0;
   questionMessage: string;
   autocompleteValue = "";
@@ -48,7 +48,11 @@ export class SelectPrompt<T extends string = string> extends AbstractPrompt<T> {
     return this.choices.filter((choice) => this.#filterChoice(choice, autocompleteValue, isCaseSensitive));
   }
 
-  #filterChoice(choice: Choice | string, autocompleteValue: string, isCaseSensitive = false) {
+  #filterChoice(
+    choice: Choice<T> | string,
+    autocompleteValue: string,
+    isCaseSensitive = false
+  ) {
     // eslint-disable-next-line no-nested-ternary
     const choiceValue = typeof choice === "string" ?
       (isCaseSensitive ? choice : choice.toLowerCase()) :

src/types.ts

@@ -1,4 +1,4 @@
-export interface Choice<T = any> {
+export interface Choice<T extends string> {
   value: T;
   label: string;
   description?: string;

src/validators.ts

@@ -10,11 +10,11 @@ export type ValidationResponse = InvalidResponse | ValidResponse;
 export type InvalidResponse = string | InvalidResponseObject;
 export type ValidResponse = null | undefined | true | ValidResponseObject;
 
-export interface PromptValidator<T = string | string[] | boolean> {
+export interface PromptValidator<T extends string | string[]> {
   validate: (input: T) => ValidationResponse;
 }
 
-export function required<T = string | string[] | boolean>(): PromptValidator<T> {
+export function required(): PromptValidator<any> {
   return {
     validate: (input) => {
       const isValid = (Array.isArray(input) ? input.length > 0 : Boolean(input));

test/types/api.test-d.ts

@@ -0,0 +1,57 @@
+// Import Third-party Dependencies
+import { expectType } from "tsd";
+
+// Import Internal Dependencies
+import {
+  question,
+  confirm,
+  select,
+  multiselect,
+  type PromptValidator
+} from "../../index.js";
+
+const stringNotEmptyValidator: PromptValidator<string> = {
+  validate(input) {
+    return input.trim().length === 0 ?
+      { isValid: false, error: "Input was empty" } :
+      { isValid: true };
+  }
+};
+
+expectType<Promise<string>>(
+  question("message", {
+    validators: [stringNotEmptyValidator]
+  })
+);
+
+expectType<Promise<"A" | "B">>(
+  select("message", { choices: ["A", "B"] })
+);
+expectType<Promise<"A" | "B">>(
+  select("message", {
+    choices: [
+      { value: "A", label: "Option A" },
+      { value: "B", label: "Option B" }
+    ]
+  })
+);
+
+expectType<Promise<("A" | "B")[]>>(
+  multiselect("message", { choices: ["A", "B"] })
+);
+expectType<Promise<("A" | "B")[]>>(
+  multiselect("message", {
+    choices: [
+      { value: "A", label: "Option A" },
+      { value: "B", label: "Option B" }
+    ],
+    preSelectedChoices: ["A"]
+  })
+);
+
+expectType<Promise<boolean>>(
+  confirm("message")
+);
+expectType<Promise<boolean>>(
+  confirm("message", { initial: true })
+);