Create Prettier install procedure

package.json

@@ -23,7 +23,8 @@
     "build": "rimraf dist && tsc --build",
     "lint": "eslint .",
     "lint:fix": "eslint --fix .",
-    "format": "prettier --write ."
+    "format": "prettier --write .",
+    "format:check": "prettier --check ."
   },
   "devDependencies": {
     "@avicenne-studio/eslint-config": "^1.0.14",

src/eslint.mts

@@ -4,10 +4,15 @@ import fs from "fs/promises";
 
 import { exec, fileExists, readJSON, writeJSON } from "./utils.mjs";
 
+const DEV_DEPENDENCIES = ["@avicenne-studio/eslint-config"];
 const CONFIG_FILE = ".eslintrc.json";
 const JSON_CONFIG = {
   extends: "@avicenne-studio",
 };
+const SCRIPTS = {
+  lint: "eslint .",
+  "lint:fix": "eslint --fix .",
+};
 
 const getExtraneousPackageConfigTask = async (): Promise<Task | undefined> => {
   const manifest = await readJSON("package.json");
@@ -35,12 +40,10 @@ const getExtraneousConfigsTasks = async (): Promise<Task | undefined> => {
   return await getExtraneousPackageConfigTask();
 };
 
-const installDevDependenciesTask = async (
-  ...packages: string[]
-): Promise<Task | undefined> => {
+const installDevDependenciesTask = async (): Promise<Task | undefined> => {
   const manifest = await readJSON("package.json");
 
-  const missing = packages.filter(
+  const missing = DEV_DEPENDENCIES.filter(
     (packageName) => !(packageName in manifest.devDependencies),
   );
   if (missing.length === 0) return;
@@ -49,6 +52,24 @@ const installDevDependenciesTask = async (
   return async () => await exec(cmd);
 };
 
+const setupScriptsTask = async (): Promise<Task | undefined> => {
+  const manifest = await readJSON("package.json");
+
+  const missing = Object.entries(SCRIPTS).filter(
+    ([script, cmd]) => manifest.scripts?.[script] !== cmd,
+  );
+  if (missing.length === 0) return;
+
+  return async () => {
+    await writeJSON(
+      "package.json",
+      merge(await readJSON("package.json"), {
+        scripts: Object.fromEntries(missing),
+      }),
+    );
+  };
+};
+
 const updateConfigTask = async (): Promise<Task | undefined> => {
   const previousConfig = await readJSON(CONFIG_FILE);
 
@@ -76,7 +97,8 @@ export default async () => {
   return (
     await Promise.all([
       getExtraneousConfigsTasks(),
-      installDevDependenciesTask("@avicenne-studio/eslint-config"),
+      installDevDependenciesTask(),
+      setupScriptsTask(),
       createConfigTask(),
     ])
   ).filter((task): task is Task => task !== undefined);

src/index.mts

@@ -1,6 +1,7 @@
 import inquirer from "inquirer";
 
 import eslint from "./eslint.mjs";
+import prettier from "./prettier.mjs";
 
 if (
   !process.stdin.isTTY ||
@@ -16,7 +17,7 @@ if (
 if (process.env.npm_config_local_prefix !== undefined)
   process.chdir(process.env.npm_config_local_prefix);
 
-const [eslintTasks] = await Promise.all([eslint()]);
+const [eslintTasks, prettierTasks] = await Promise.all([eslint(), prettier()]);
 
 const prompts = [];
 
@@ -29,7 +30,15 @@ if (eslintTasks.length !== 0) {
   });
 }
 
-// TODO: Prettier
+if (prettierTasks.length !== 0) {
+  prompts.push({
+    name: "prettier",
+    type: "confirm",
+    message: "Would you like to install Prettier?",
+    suffix: "",
+  });
+}
+
 // TODO: husky
 // TODO: GitHub Actions
 // TODO: PR templates
@@ -40,4 +49,5 @@ const answers = await inquirer.prompt(prompts);
 
 await Promise.all([
   ...(answers.eslint ? eslintTasks.map(async (task) => await task()) : []),
+  ...(answers.prettier ? prettierTasks.map(async (task) => await task()) : []),
 ]);

src/prettier.mts

@@ -0,0 +1,95 @@
+import merge from "deepmerge";
+import fs from "fs/promises";
+
+import { exec, fileExists, readJSON, writeJSON } from "./utils.mjs";
+
+const DEV_DEPENDENCIES = ["@avicenne-studio/prettier-config"];
+const CONFIG_FILE = ".prettierrc.json";
+const JSON_CONFIG = "@avicenne-studio/prettier-config";
+const SCRIPTS = {
+  format: "prettier --write .",
+  "format:check": "prettier --check .",
+};
+
+const getExtraneousPackageConfigTask = async (): Promise<Task | undefined> => {
+  const manifest = await readJSON("package.json");
+
+  if (!("prettier" in manifest)) return;
+
+  return () => {
+    throw new Error(
+      `Extraneous Prettier config found in package.json. Delete it to continue.`,
+    );
+  };
+};
+
+const getExtraneousConfigsTasks = async (): Promise<Task | undefined> => {
+  for (const file of await fs.readdir(".")) {
+    if (file === CONFIG_FILE || !file.startsWith(".prettierrc")) continue;
+
+    return () => {
+      throw new Error(
+        `Extraneous Prettier config file found: ${file}. Delete it to continue.`,
+      );
+    };
+  }
+
+  return await getExtraneousPackageConfigTask();
+};
+
+const installDevDependenciesTask = async (): Promise<Task | undefined> => {
+  const manifest = await readJSON("package.json");
+
+  const missing = DEV_DEPENDENCIES.filter(
+    (packageName) => !(packageName in manifest.devDependencies),
+  );
+  if (missing.length === 0) return;
+
+  const cmd = `npm install --save-dev ${missing.map((packageName) => JSON.stringify(packageName)).join(" ")}`;
+  return async () => await exec(cmd);
+};
+
+const setupScriptsTask = async (): Promise<Task | undefined> => {
+  const manifest = await readJSON("package.json");
+
+  const missing = Object.entries(SCRIPTS).filter(
+    ([script, cmd]) => manifest.scripts?.[script] !== cmd,
+  );
+  if (missing.length === 0) return;
+
+  return async () => {
+    await writeJSON(
+      "package.json",
+      merge(await readJSON("package.json"), {
+        scripts: Object.fromEntries(missing),
+      }),
+    );
+  };
+};
+
+const updateConfigTask = async (): Promise<Task | undefined> => {
+  const previousConfig = await readJSON(CONFIG_FILE);
+
+  if (previousConfig === JSON_CONFIG) return;
+
+  return async () => await writeJSON(CONFIG_FILE, JSON_CONFIG);
+};
+
+const createConfigTask = async (): Promise<Task | undefined> => {
+  if (await fileExists(CONFIG_FILE)) return await updateConfigTask();
+
+  return async () => {
+    await writeJSON(CONFIG_FILE, JSON_CONFIG);
+  };
+};
+
+export default async () => {
+  return (
+    await Promise.all([
+      getExtraneousConfigsTasks(),
+      installDevDependenciesTask(),
+      setupScriptsTask(),
+      createConfigTask(),
+    ])
+  ).filter((task): task is Task => task !== undefined);
+};

src/utils.mts

@@ -17,7 +17,7 @@ export const readJSON = async (path: string) => {
   return JSON.parse(await fs.readFile(path, "utf8"));
 };
 
-export const writeJSON = async (path: string, json: object) => {
+export const writeJSON = async (path: string, json: unknown) => {
   await fs.writeFile(
     path,
     await prettier.format(JSON.stringify(json, null, "  "), {