feat: Implement dead-simple dotenv for bootstrap

package.json

@@ -36,7 +36,6 @@
 	"author": "nondanee, 1715173329, pan93412",
 	"license": "LGPL-3.0-only",
 	"dependencies": {
-		"dotenv": "^16.3.1",
 		"node-windows": "^1.0.0-beta.8",
 		"pino": "6.14.0",
 		"pino-pretty": "^7.6.1"

src/bootstrap/index.js

@@ -1,14 +1,17 @@
-const dotenv = require('dotenv');
+// @ts-check
+
+const { loadDotenv } = require('../dotenv.js');
 const devMessage = require('./message');
 
 /**
  * Start the main part.
  *
  * @param {string} mainEntry
+ * @returns {Promise<void>}
  */
-function startApp(mainEntry) {
+async function startApp(mainEntry) {
 	// Inject the `.env` file into the `process.env` object.
-	dotenv.config();
+	await loadDotenv();
 
 	if (process.env.DEVELOPMENT === 'true') {
 		console.warn(devMessage);

src/dotenv.js

@@ -0,0 +1,98 @@
+/**
+ * A very simple dotenv implementation.
+ */
+
+//@ts-check
+
+const fs = require('fs');
+const readline = require('readline');
+const path = require('path');
+
+/**
+ * Parse .env file.
+ *
+ * @param {string} filePath
+ * @returns {Promise<Record<string, string>>}
+ */
+async function parseDotenv(filePath) {
+	const env = /**@type {Record<string, string>}*/ ({});
+	const rl = readline.createInterface({
+		input: fs.createReadStream(filePath),
+		crlfDelay: Infinity,
+	});
+
+	for await (const line of rl) {
+		if (line.startsWith('#')) continue;
+
+		const [key, value] = line.split('=', 2);
+		env[key.trimEnd()] = value.trimStart();
+	}
+
+	return env;
+}
+
+/**
+ * Find .env file.
+ *
+ * @returns {Promise<string|null>}
+ */
+async function findEnv() {
+	const cwd = process.cwd();
+	const envPath = path.join(cwd, '.env');
+
+	try {
+		await fs.promises.access(envPath, fs.constants.R_OK);
+		return envPath;
+	} catch (err) {
+		return null;
+	}
+}
+
+/**
+ * Inject environment variables into process.env.
+ *
+ * @param {Record<string, string>} env
+ * @returns {void}
+ */
+function injectEnv(env) {
+	// https://github.com/motdotla/dotenv/blob/aa03dcad1002027390dac1e8d96ac236274de354/lib/main.js#L277
+	for (const [key, value] of Object.entries(env)) {
+		// the priority of .env is lower than process.env
+		// due to Node.js 12, we don't use nullish coalescing operator
+		process.env[key] = process.env[key] == null ? value : process.env[key];
+	}
+
+	return;
+}
+
+/**
+ * A simple method for finding .env file and injecting
+ * environment variables into process.env.
+ *
+ * No exceptions will be raised – we have handled errors
+ * inside this code.
+ *
+ * @returns {Promise<void>}
+ */
+async function loadDotenv() {
+	const envPath = await findEnv();
+	if (envPath == null) {
+		return;
+	}
+
+	try {
+		const env = await parseDotenv(envPath);
+		injectEnv(env);
+	} catch (e) {
+		console.error(e);
+	}
+
+	return;
+}
+
+module.exports = {
+	loadDotenv,
+	injectEnv,
+	findEnv,
+	parseDotenv,
+};

yarn.lock

@@ -1206,7 +1206,6 @@ __metadata:
     browserslist: ^4.21.9
     core-js: ^3.31.1
     cross-env: ^7.0.3
-    dotenv: ^16.3.1
     jest: ^29.6.1
     node-windows: ^1.0.0-beta.8
     pino: 6.14.0