fix(vite): .env files not being loaded (#3416)

Fixes #3364

Author: marvinhagemeister

deno.json

@@ -44,6 +44,7 @@
     "@fresh/build-id": "jsr:@fresh/build-id@^1.0.0",
     "@std/cli": "jsr:@std/cli@^1.0.19",
     "@std/collections": "jsr:@std/collections@^1.1.2",
+    "@std/dotenv": "jsr:@std/dotenv@^0.225.5",
     "@std/http": "jsr:@std/http@^1.0.15",
     "@std/uuid": "jsr:@std/uuid@^1.0.7",
     "@types/node": "npm:@types/node@^24.3.0",

deno.lock

@@ -0,0 +1,2 @@
+MY_ENV="MY_ENV test value"
+VITE_MY_ENV="VITE_MY_ENV test value"

packages/plugin-vite/demo/.env

@@ -0,0 +1,2 @@
+MY_LOCAL_ENV="MY_LOCAL_ENV test value"
+VITE_MY_LOCAL_ENV="VITE_MY_LOCAL_ENV test value"

packages/plugin-vite/demo/.env.local

@@ -0,0 +1,10 @@
+export const handler = () => {
+  const json = {
+    MY_ENV: Deno.env.get("MY_ENV"),
+    VITE_MY_ENV: Deno.env.get("VITE_MY_ENV"),
+    MY_LOCAL_ENV: Deno.env.get("MY_LOCAL_ENV"),
+    VITE_MY_LOCAL_ENV: Deno.env.get("VITE_MY_LOCAL_ENV"),
+  };
+
+  return Response.json(json);
+};

packages/plugin-vite/demo/routes/tests/env_files.tsx

@@ -22,6 +22,8 @@ import {
 } from "@fresh/core/internal-dev";
 import { checkImports } from "./plugins/verify_imports.ts";
 import { isBuiltin } from "node:module";
+import { load as stdLoadEnv } from "@std/dotenv";
+import path from "node:path";
 
 export function fresh(config?: FreshViteConfig): Plugin[] {
   const fConfig: ResolvedFreshViteConfig = {
@@ -48,10 +50,14 @@ export function fresh(config?: FreshViteConfig): Plugin[] {
     }
   });
 
+  let isDev = false;
+
   const plugins: Plugin[] = [
     {
       name: "fresh",
       config(config, env) {
+        isDev = env.command === "serve";
+
         return {
           esbuild: {
             jsx: "automatic",
@@ -151,7 +157,7 @@ export function fresh(config?: FreshViteConfig): Plugin[] {
           },
         };
       },
-      configResolved(vConfig) {
+      async configResolved(vConfig) {
         // Run update check in background
         updateCheck(UPDATE_INTERVAL).catch(() => {});
 
@@ -163,6 +169,17 @@ export function fresh(config?: FreshViteConfig): Plugin[] {
           const name = fConfig.namer.getUniqueName(specName);
           fConfig.islandSpecifiers.set(spec, name);
         });
+
+        const envDir = pathWithRoot(
+          vConfig.envDir || vConfig.root,
+          vConfig.root,
+        );
+
+        await loadEnvFile(path.join(envDir, ".env"));
+        await loadEnvFile(path.join(envDir, ".env.local"));
+        const mode = isDev ? "development" : "production";
+        await loadEnvFile(path.join(envDir, `.env.${mode}`));
+        await loadEnvFile(path.join(envDir, `.env.${mode}.local`));
       },
     },
     serverEntryPlugin(fConfig),
@@ -190,3 +207,11 @@ export function fresh(config?: FreshViteConfig): Plugin[] {
 
   return plugins;
 }
+
+async function loadEnvFile(envPath: string) {
+  try {
+    await stdLoadEnv({ envPath, export: true });
+  } catch {
+    // Ignoe
+  }
+}

packages/plugin-vite/src/mod.ts

@@ -453,3 +453,24 @@ Deno.test({
   sanitizeOps: false,
   sanitizeResources: false,
 });
+
+Deno.test({
+  name: "vite build - env files",
+  fn: async () => {
+    await launchProd(
+      { cwd: viteResult.tmp },
+      async (address) => {
+        const res = await fetch(`${address}/tests/env_files`);
+        const json = await res.json();
+        expect(json).toEqual({
+          MY_ENV: "MY_ENV test value",
+          VITE_MY_ENV: "VITE_MY_ENV test value",
+          MY_LOCAL_ENV: "MY_LOCAL_ENV test value",
+          VITE_MY_LOCAL_ENV: "VITE_MY_LOCAL_ENV test value",
+        });
+      },
+    );
+  },
+  sanitizeOps: false,
+  sanitizeResources: false,
+});

packages/plugin-vite/tests/build_test.ts

@@ -403,3 +403,19 @@ Deno.test({
   sanitizeOps: false,
   sanitizeResources: false,
 });
+
+Deno.test({
+  name: "vite dev - load .env files",
+  fn: async () => {
+    const res = await fetch(`${demoServer.address()}/tests/env_files`);
+    const json = await res.json();
+    expect(json).toEqual({
+      MY_ENV: "MY_ENV test value",
+      VITE_MY_ENV: "VITE_MY_ENV test value",
+      MY_LOCAL_ENV: "MY_LOCAL_ENV test value",
+      VITE_MY_LOCAL_ENV: "VITE_MY_LOCAL_ENV test value",
+    });
+  },
+  sanitizeOps: false,
+  sanitizeResources: false,
+});