feat: prompt for values in hydration too (#505)

## PR Checklist

- [x] Addresses an existing open issue: fixes #500
- [x] That issue was marked as [`status: accepting
prs`](https://github.com/JoshuaKGoldberg/template-typescript-node-package/issues?q=is%3Aopen+is%3Aissue+label%3A%22status%3A+accepting+prs%22)
- [x] Steps in
[CONTRIBUTING.md](https://github.com/JoshuaKGoldberg/template-typescript-node-package/blob/main/.github/CONTRIBUTING.md)
were taken

## Overview

Extracts the prompting logic from _setup_ out to a `PrefillPrompter`
class, and re-uses that class in _hydration_.

There was some defaults-checking (`owner`, `title`) that actually wasn't
necessary anymore.

Author: JoshuaKGoldberg

src/hydrate/hydrate.ts

@@ -12,10 +12,10 @@ import { finalizeDependencies as finalizeDependencies } from "./steps/finalizeDe
 import { writeReadme } from "./steps/writeReadme.js";
 import { writeStructure } from "./steps/writing/writeStructure.js";
 import { getHydrationDefaults } from "./values/getHydrationDefaults.js";
-import { ensureHydrationInputValues } from "./values/hydrationInputValues.js";
+import { augmentWithHydrationValues } from "./values/hydrationInputValues.js";
 
 export async function hydrate(args: string[]) {
-	const { values: hydrationValues } = parseArgs({
+	const { values: hydrationSkips } = parseArgs({
 		args,
 		options: {
 			"skip-install": { type: "boolean" },
@@ -30,35 +30,38 @@ export async function hydrate(args: string[]) {
 		defaults: await getHydrationDefaults(),
 		label: "hydration",
 		run: async ({ octokit, values }) => {
-			ensureHydrationInputValues(values);
+			const hydrationValues = await augmentWithHydrationValues(values);
 
 			await withSpinner(clearUnnecessaryFiles, "clearing unnecessary files");
 
 			await withSpinner(
-				() => writeStructure(values),
+				() => writeStructure(hydrationValues),
 				"writing new repository structure"
 			);
 
-			await withSpinner(() => writeReadme(values), "writing README.md");
+			await withSpinner(
+				() => writeReadme(hydrationValues),
+				"writing README.md"
+			);
 
-			if (hydrationValues["skip-install"]) {
+			if (hydrationSkips["skip-install"]) {
 				skipSpinnerBlock(`Skipping package installations.`);
 			} else {
 				await withSpinner(
-					() => finalizeDependencies(values),
+					() => finalizeDependencies(hydrationValues),
 					"finalizing dependencies"
 				);
 			}
 
-			if (hydrationValues["skip-setup"]) {
+			if (hydrationSkips["skip-setup"]) {
 				skipSpinnerBlock(`Done hydrating, and skipping setup command.`);
 			} else {
 				successSpinnerBlock("Done hydrating. Starting setup command...");
 
 				await setupWithInformation({
 					octokit,
 					values: {
-						...values,
+						...hydrationValues,
 						skipUninstalls: true,
 					},
 				});

src/hydrate/values/getHydrationDefaults.ts

@@ -11,6 +11,7 @@ interface PartialPackageData {
 	name?: string;
 	repository?: string;
 }
+
 export async function getHydrationDefaults() {
 	const existingReadme = await readFileSafe("./README.md", "");
 	const existingPackage = JSON.parse(

src/hydrate/values/hydrationInputValues.test.ts

@@ -1,39 +1,20 @@
 import { InputValues } from "../../shared/inputs.js";
-import { HydrationInputValues } from "./types.js";
+import { PrefillPrompter } from "../../shared/PrefillPrompter.js";
 
-type NullableProperties<T> = {
-	[K in keyof T]: T[K] | undefined;
-};
+export async function augmentWithHydrationValues(values: InputValues) {
+	const prompter = new PrefillPrompter();
 
-export function ensureHydrationInputValues(
-	values: NullableProperties<InputValues>
-): asserts values is HydrationInputValues {
-	const complaints: string[] = [];
-
-	for (const [key, suggestion] of [
-		["description", "add a 'description' to package.json"],
-		["repository", "add a 'name' to package.json"],
-		[
+	return {
+		...values,
+		author: await prompter.getPrefillOrPromptedValue(
 			"author",
-			"add an 'author' to package.json like \"Your Name <[email protected]>\" or an { email, name } object",
-		],
-		[
+			values.author,
+			"What author will be used for the owner?"
+		),
+		email: await prompter.getPrefillOrPromptedValue(
 			"email",
-			"add an 'author' to package.json like \"Your Name <[email protected]>\" or an { email, name } object",
-		],
-		["owner", "add an 'origin' git remote"],
-		["title", "add an h1 to the README.md"],
-	] as const) {
-		if (!values[key]) {
-			complaints.push(
-				`- Could not determine ${key}. Please ${suggestion}, or provide with --${key}.`
-			);
-		}
-	}
-
-	if (complaints.length) {
-		throw new Error(
-			`Failed to determine repository settings:\n${complaints.join("\n")}`
-		);
-	}
+			values.email,
+			"What email will be used for the owner?"
+		),
+	};
 }

src/hydrate/values/hydrationInputValues.ts

@@ -0,0 +1,75 @@
+import chalk from "chalk";
+import { describe, expect, it, vi } from "vitest";
+
+import { PrefillPrompter } from "./PrefillPrompter.js";
+
+const mockText = vi.fn();
+
+vi.mock("@clack/prompts", () => ({
+	isCancel: () => false,
+	get text() {
+		return mockText;
+	},
+}));
+
+const mockLogLine = vi.fn();
+
+vi.mock("./cli/lines.js", () => ({
+	get logLine() {
+		return mockLogLine;
+	},
+}));
+
+describe("PrefillPrompter", () => {
+	it("logs a line and a pre-fill message when a first value already exists", async () => {
+		const prompter = new PrefillPrompter();
+		const existing = "existing value";
+
+		const actual = await prompter.getPrefillOrPromptedValue(
+			"key",
+			existing,
+			""
+		);
+
+		expect(actual).toEqual(existing);
+		expect(mockLogLine.mock.calls).toEqual([
+			[],
+			[chalk.gray(`Pre-filling key to existing value.`)],
+		]);
+	});
+
+	it("logs only a pre-fill message when a second value already exists", async () => {
+		const prompter = new PrefillPrompter();
+
+		await prompter.getPrefillOrPromptedValue("key 1", "existing 1", "");
+
+		const actual = await prompter.getPrefillOrPromptedValue(
+			"key 2",
+			"existing 2",
+			""
+		);
+
+		expect(actual).toEqual("existing 2");
+		expect(mockLogLine.mock.calls).toEqual([
+			[],
+			[chalk.gray(`Pre-filling key 1 to existing 1.`)],
+			[chalk.gray(`Pre-filling key 2 to existing 2.`)],
+		]);
+	});
+
+	it("prompts for a new value when the value doesn't already exist", async () => {
+		const prompter = new PrefillPrompter();
+		const expected = "expected value";
+
+		mockText.mockResolvedValue(expected);
+
+		const actual = await prompter.getPrefillOrPromptedValue(
+			"key",
+			undefined,
+			""
+		);
+
+		expect(actual).toEqual(expected);
+		expect(mockLogLine).not.toHaveBeenCalled();
+	});
+});

src/shared/PrefillPrompter.test.ts

@@ -0,0 +1,44 @@
+import * as prompts from "@clack/prompts";
+import chalk from "chalk";
+
+import { logLine } from "./cli/lines.js";
+import { handlePromptCancel } from "./prompts.js";
+
+export class PrefillPrompter {
+	#shouldLogLineBeforePrefill = true;
+
+	async getPrefillOrPromptedValue(
+		key: string,
+		existingValue: string | undefined,
+		message: string,
+		placeholder?: string
+	) {
+		if (existingValue) {
+			if (this.#shouldLogLineBeforePrefill) {
+				logLine();
+				this.#shouldLogLineBeforePrefill = false;
+			}
+
+			logLine(chalk.gray(`Pre-filling ${key} to ${existingValue}.`));
+			return existingValue;
+		}
+
+		const value = await prompts.text({
+			message,
+			placeholder,
+			validate: (val) => {
+				if (val.length === 0) {
+					return "Please enter a value.";
+				}
+			},
+		});
+
+		handlePromptCancel(value);
+
+		return value;
+	}
+
+	reset() {
+		this.#shouldLogLineBeforePrefill = true;
+	}
+}