feat: add DotEnv support

packages/webpack5/src/helpers/dotEnv.ts

@@ -0,0 +1,49 @@
+import DotEnvPlugin from 'dotenv-webpack';
+import Config from 'webpack-chain';
+import { resolve } from 'path';
+
+import { getProjectRootPath } from './project';
+import { env } from '..';
+import { existsSync } from 'fs';
+
+/**
+ * @internal
+ */
+export function applyDotEnvPlugin(config: Config) {
+	const path = getDotEnvPath();
+
+	config.when(path !== null, (config) => {
+		config.plugin('DotEnvPlugin').use(DotEnvPlugin, [
+			{
+				path: getDotEnvPath(),
+				silent: true, // hide any errors
+			},
+		]);
+	});
+}
+
+function getDotEnvFileName(): string {
+	if (env.env) {
+		return `.env.${env.env}`;
+	}
+
+	return '.env';
+}
+
+function getDotEnvPath(): string {
+	const dotEnvPath = resolve(getProjectRootPath(), '.env');
+	const dotEnvWithEnvPath = resolve(getProjectRootPath(), getDotEnvFileName());
+
+	// look for .env.<env>
+	if (existsSync(dotEnvWithEnvPath)) {
+		return dotEnvWithEnvPath;
+	}
+
+	// fall back to .env
+	if (existsSync(dotEnvPath)) {
+		return dotEnvPath;
+	}
+
+	// don't use .env
+	return null;
+}