refactor(validators)!: remove error field (#117)

README.md

@@ -54,18 +54,21 @@ Simple prompt, similar to `rl.question()` with an improved UI.
 
 Use `options.secure` if you need to hide both input and answer.
 
-Use `options.validators` to handle user input.
-
 Use `options.signal` to set an `AbortSignal` (throws a [AbortError](#aborterror)).
 
+Use `options.validators` to handle user input.
+
 **Example**
 
 ```js
 const packageName = await question('Package name', {
   validators: [
     {
-      validate: (value) => !existsSync(join(process.cwd(), value)),
-      error: (value) => `Folder ${value} already exists`
+      validate: (value) => {
+        if (!existsSync(join(process.cwd(), value))) {
+          return `Folder ${value} already exists`
+        }
+      }
     }
   ]
 });

src/prompts/multiselect.ts

@@ -9,7 +9,7 @@ import wcwidth from "@topcli/wcwidth";
 import { AbstractPrompt, AbstractPromptOptions } from "./abstract.js";
 import { stripAnsi } from "../utils.js";
 import { SYMBOLS } from "../constants.js";
-import { PromptValidator } from "../validators.js";
+import { isValid, PromptValidator, resultError } from "../validators.js";
 import { Choice } from "../types.js";
 
 // CONSTANTS
@@ -247,9 +247,10 @@ export class MultiselectPrompt extends AbstractPrompt<string | string[]> {
       });
 
       for (const validator of this.#validators) {
-        if (!validator.validate(values)) {
-          const error = validator.error(values);
-          render({ error });
+        const validationResult = validator.validate(values);
+
+        if (isValid(validationResult) === false) {
+          render({ error: resultError(validationResult) });
 
           return;
         }

src/prompts/question.ts

@@ -9,7 +9,7 @@ import wcwidth from "@topcli/wcwidth";
 import { AbstractPrompt, AbstractPromptOptions } from "./abstract.js";
 import { stripAnsi } from "../utils.js";
 import { SYMBOLS } from "../constants.js";
-import { PromptValidator } from "../validators.js";
+import { isValid, PromptValidator, resultError } from "../validators.js";
 
 export interface QuestionOptions extends AbstractPromptOptions {
   defaultValue?: string;
@@ -86,9 +86,10 @@ export class QuestionPrompt extends AbstractPrompt<string> {
     this.stdout.clearScreenDown();
 
     for (const validator of this.#validators) {
-      if (!validator.validate(this.answer!)) {
-        const error = validator.error(this.answer!);
-        this.#setQuestionSuffixError(error);
+      const validationResult = validator.validate(this.answer!);
+
+      if (isValid(validationResult) === false) {
+        this.#setQuestionSuffixError(resultError(validationResult));
         this.answerBuffer = this.#question();
 
         return;

src/prompts/select.ts

@@ -9,7 +9,7 @@ import wcwidth from "@topcli/wcwidth";
 import { AbstractPrompt, AbstractPromptOptions } from "./abstract.js";
 import { stripAnsi } from "../utils.js";
 import { SYMBOLS } from "../constants.js";
-import { PromptValidator } from "../validators.js";
+import { isValid, PromptValidator, resultError } from "../validators.js";
 import { Choice } from "../types.js";
 
 // CONSTANTS
@@ -199,9 +199,10 @@ export class SelectPrompt extends AbstractPrompt<string> {
       const value = typeof choice === "string" ? choice : choice.value;
 
       for (const validator of this.#validators) {
-        if (!validator.validate(value)) {
-          const error = validator.error(value);
-          render({ error });
+        const validationResult = validator.validate(value);
+
+        if (isValid(validationResult) === false) {
+          render({ error: resultError(validationResult) });
 
           return;
         }

src/validators.ts

@@ -1,11 +1,45 @@
+export type ValidResponseObject = {
+  isValid?: true;
+}
+export type InvalidResponseObject = {
+  isValid: false;
+  error: string;
+}
+export type ValidationResponseObject = ValidResponseObject | InvalidResponseObject;
+export type ValidationResponse = InvalidResponse | ValidResponse;
+export type InvalidResponse = string | InvalidResponseObject;
+export type ValidResponse = null | undefined | true | ValidResponseObject;
+
 export interface PromptValidator<T = string | string[] | boolean> {
-  validate: (input: T) => boolean;
-  error: (input: T) => string;
+  validate: (input: T) => ValidationResponse;
 }
 
 export function required<T = string | string[] | boolean>(): PromptValidator<T> {
   return {
-    validate: (input) => (Array.isArray(input) ? input.length > 0 : Boolean(input)),
-    error: () => "required"
+    validate: (input) => {
+      const isValid = (Array.isArray(input) ? input.length > 0 : Boolean(input));
+
+      return isValid ? null : { isValid, error: "required" };
+    }
   };
 }
+
+export function isValid(result: ValidationResponse): result is ValidResponse {
+  if (typeof result === "object") {
+    return result?.isValid !== false;
+  }
+
+  if (typeof result === "string") {
+    return result.length > 0;
+  }
+
+  return true;
+}
+
+export function resultError(result: InvalidResponse) {
+  if (typeof result === "object") {
+    return result.error;
+  }
+
+  return result;
+}

test/question-prompt.test.ts

@@ -66,8 +66,14 @@ describe("QuestionPrompt", () => {
     const questionPrompt = await TestingPrompt.QuestionPrompt("What's your name?", {
       input: ["test1", "test10", "test2"],
       validators: [{
-        validate: (input) => !(input as string).startsWith("test1"),
-        error: (input) => `Value cannot start with 'test1', given ${input}.`
+        validate: (input) => {
+          const isValid = !(input as string).startsWith("test1");
+          if (!isValid) {
+            return { isValid, error: `Value cannot start with 'test1', given ${input}.` };
+          }
+
+          return void 0;
+        }
       }],
       onStdoutWrite: (log) => logs.push(log)
     });

test/validators.test.ts

@@ -0,0 +1,65 @@
+// Import Node.js Dependencies
+import assert from "node:assert";
+import { describe, it } from "node:test";
+
+import { InvalidResponseObject, isValid, resultError, ValidationResponseObject } from "../src/validators.js";
+
+describe("Validators", () => {
+  describe("isValid", () => {
+    const testCases = [
+      {
+        input: "test",
+        expected: true
+      },
+      {
+        input: "",
+        expected: false
+      },
+      {
+        input: null,
+        expected: true
+      },
+      {
+        input: undefined,
+        expected: true
+      },
+      {
+        input: { isValid: true } as ValidationResponseObject,
+        expected: true
+      },
+      {
+        input: { isValid: false, error: "boo" } as ValidationResponseObject,
+        expected: false
+      }
+    ];
+
+    for (const testCase of testCases) {
+      it(`given '${formatInput(testCase.input)}', it should return ${testCase.expected}`, () => {
+        assert.strictEqual(isValid(testCase.input), testCase.expected);
+      });
+    }
+  });
+
+  describe("resultError", () => {
+    it("should return the error message given an object", () => {
+      const error = "required";
+      const result: InvalidResponseObject = { isValid: false, error };
+
+      assert.strictEqual(resultError(result), error);
+    });
+
+    it("should return the error message given a string", () => {
+      const error = "required";
+
+      assert.strictEqual(resultError(error), error);
+    });
+  });
+});
+
+function formatInput(input) {
+  if (typeof input === "object") {
+    return JSON.stringify(input);
+  }
+
+  return input;
+}