fix: trim preceding ./ from package.json bin (#2084)

## PR Checklist

- [x] Addresses an existing open issue: fixes #2081
- [x] That issue was marked as [`status: accepting
prs`](https://github.com/JoshuaKGoldberg/create-typescript-app/issues?q=is%3Aopen+is%3Aissue+label%3A%22status%3A+accepting+prs%22)
- [x] Steps in
[CONTRIBUTING.md](https://github.com/JoshuaKGoldberg/create-typescript-app/blob/main/.github/CONTRIBUTING.md)
were taken

## Overview

🎁

Author: JoshuaKGoldberg

src/base.ts

@@ -7,6 +7,7 @@ import { z } from "zod";
 import { readAccess } from "./options/readAccess.js";
 import { readAllContributors } from "./options/readAllContributors.js";
 import { readAuthor } from "./options/readAuthor.js";
+import { readBin } from "./options/readBin.js";
 import { readDescription } from "./options/readDescription.js";
 import { readDocumentation } from "./options/readDocumentation.js";
 import { readEmailFromCodeOfConduct } from "./options/readEmailFromCodeOfConduct.js";
@@ -181,7 +182,7 @@ export const base = createBase({
 				await readAuthor(getPackageAuthor, getNpmDefaults, options.owner),
 		);
 
-		const getBin = lazyValue(async () => (await getPackageData()).bin);
+		const getBin = lazyValue(async () => await readBin(getPackageData));
 
 		const getEmoji = lazyValue(async () => await readEmoji(getDescription));
 

src/options/readBin.test.ts

@@ -0,0 +1,41 @@
+import { describe, expect, it } from "vitest";
+
+import { readBin } from "./readBin.js";
+
+describe(readBin, () => {
+	it("resolves with undefined when package data has no bin", async () => {
+		const getPackageData = () => Promise.resolve({});
+
+		const actual = await readBin(getPackageData);
+
+		expect(actual).toBe(undefined);
+	});
+
+	it("resolves with a trimmed string when the package data has a string bin", async () => {
+		const getPackageData = () =>
+			Promise.resolve({
+				bin: "./index.js",
+			});
+
+		const actual = await readBin(getPackageData);
+
+		expect(actual).toBe("index.js");
+	});
+
+	it("resolves with an object of trimmed bins when the package data has a string bin", async () => {
+		const getPackageData = () =>
+			Promise.resolve({
+				bin: {
+					absolute: "index.js",
+					relative: "./index.js",
+				},
+			});
+
+		const actual = await readBin(getPackageData);
+
+		expect(actual).toEqual({
+			absolute: "index.js",
+			relative: "index.js",
+		});
+	});
+});

src/options/readBin.ts

@@ -0,0 +1,17 @@
+import { PartialPackageData } from "../types.js";
+import { trimPrecedingSlash } from "../utils/trimPrecedingSlash.js";
+
+export async function readBin(
+	getPackageData: () => Promise<PartialPackageData>,
+) {
+	const { bin } = await getPackageData();
+
+	return typeof bin === "object"
+		? (Object.fromEntries(
+				Object.entries(bin).map(([key, value]) => [
+					key,
+					trimPrecedingSlash(value),
+				]),
+			) as typeof bin)
+		: trimPrecedingSlash(bin);
+}

src/utils/trimPrecedingSlash.test.ts

@@ -0,0 +1,15 @@
+import { describe, expect, test } from "vitest";
+
+import { trimPrecedingSlash } from "./trimPrecedingSlash.js";
+
+describe(trimPrecedingSlash, () => {
+	test.each([
+		[undefined, undefined],
+		["", ""],
+		["a", "a"],
+		["./a", "a"],
+	])("%s becomes %s", (input, expected) => {
+		const actual = trimPrecedingSlash(input);
+		expect(actual).toBe(expected);
+	});
+});

src/utils/trimPrecedingSlash.ts

@@ -0,0 +1,3 @@
+export function trimPrecedingSlash(filePath: string | undefined) {
+	return filePath?.replace(/^\.\//, "");
+}