feat(dev): support .env.local (#3516)

Author: gioboa

docs/1.guide/97.configuration.md

@@ -69,7 +69,7 @@ export default defineEventHandler((event) => {
 
 ### Local development
 
-Finally, you can update the runtime config using environment variables. You can use a `.env` file in development and use platform variables in production (see below).
+Finally, you can update the runtime config using environment variables. You can use a `.env` or `.env.local` file in development and use platform variables in production (see below).
 
 Create an `.env` file in your project root:
 

docs/2.deploy/20.providers/cloudflare.md

@@ -179,22 +179,22 @@ export default defineEventHandler((event) => {
 
 ### Specify Variables in Development Mode
 
-For development, you can use a `.env` file to specify environment variables:
+For development, you can use a `.env` or `.env.local` file to specify environment variables:
 
 ```ini
 NITRO_HELLO_THERE="captain"
 SECRET="top-secret"
 ```
 
 ::note
-**Note:** Make sure you add `.env` to the `.gitignore` file so that you don't commit it as it can contain sensitive information.
+**Note:** Make sure you add `.env` and `.env.local` to the `.gitignore` file so that you don't commit it as it can contain sensitive information.
 ::
 
 ### Specify Variables for local previews
 
 After build, when you try out your project locally with `wrangler dev` or `wrangler pages dev`, in order to have access to environment variables you will need to specify the in a `.dev.vars` file in the root of your project (as presented in the [Pages](https://developers.cloudflare.com/pages/functions/bindings/#interact-with-your-environment-variables-locally) and [Workers](https://developers.cloudflare.com/workers/configuration/environment-variables/#interact-with-environment-variables-locally) documentation).
 
-If you are using a `.env` file while developing, your `.dev.vars` should be identical to it.
+If you are using a `.env` or `.env.local` file while developing, your `.dev.vars` should be identical to it.
 
 ::note
 **Note:** Make sure you add `.dev.vars` to the `.gitignore` file so that you don't commit it as it can contain sensitive information.

src/config/loader.ts

@@ -85,14 +85,18 @@ async function _loadUserConfig(
   // prettier-ignore
   let preset: string | undefined = (configOverrides.preset as string) || process.env.NITRO_PRESET || process.env.SERVER_PRESET
 
+  const _dotenv =
+    opts.dotenv ??
+    (configOverrides.dev && { fileName: [".env", ".env.local"] });
   const loadedConfig = await (
     opts.watch
       ? watchConfig<NitroConfig & { _meta?: NitroPresetMeta }>
       : loadConfig<NitroConfig & { _meta?: NitroPresetMeta }>
   )({
     name: "nitro",
     cwd: configOverrides.rootDir,
-    dotenv: opts.dotenv ?? configOverrides.dev,
+    // @ts-expect-error
+    dotenv: _dotenv,
     extend: { extendKey: ["extends", "preset"] },
     defaults: NitroDefaults,
     jitiOptions: {