Add passEnv config option

packages/next-server/lib/pass-env.ts

@@ -0,0 +1,8 @@
+export default function passEnv() {
+  let passEnv: { [x: string]: string | undefined } | undefined
+  if (process.env.__NEXT_ENV_PASS) process.env.__NEXT_ENV_PASS.split(',').forEach((key) => {
+    passEnv ? passEnv[key] = process.env[key] : passEnv = {[key]: process.env[key]}
+  })
+
+  return passEnv
+}

packages/next-server/server/render.tsx

@@ -9,6 +9,7 @@ import Loadable from '../lib/loadable'
 import LoadableCapture from '../lib/loadable-capture'
 import {getDynamicImportBundles, Manifest as ReactLoadableManifest, ManifestItem} from './get-dynamic-import-bundles'
 import {getPageFiles, BuildManifest} from './get-page-files'
+import passEnv from '../lib/pass-env'
 
 type Enhancer = (Component: React.ComponentType) => React.ComponentType
 type ComponentsEnhancer = {enhanceApp?: Enhancer, enhanceComponent?: Enhancer}|Enhancer
@@ -95,6 +96,7 @@ function renderDocument(Document: React.ComponentType, {
         buildId, // buildId is used to facilitate caching of page bundles, we send it to the client so that pageloader knows where to load bundles
         assetPrefix: assetPrefix === '' ? undefined : assetPrefix, // send assetPrefix to the client side when configured, otherwise don't sent in the resulting HTML
         runtimeConfig, // runtimeConfig if provided, otherwise don't sent in the resulting HTML
+        passEnv: passEnv(), // when setting config option passEnv
         nextExport, // If this is a page exported by `next export`
         dynamicIds: dynamicImportsIds.length === 0 ? undefined : dynamicImportsIds,
         err: (err) ? serializeError(dev, err) : undefined, // Error if one happened, otherwise don't sent in the resulting HTML

packages/next/build/webpack-config.js

@@ -302,6 +302,7 @@ export default async function getBaseWebpackConfig (dir, {dev = false, isServer
             }
           }, {}) : {},
         {
+          'process.env.__NEXT_ENV_PASS': JSON.stringify(config.passEnv.join(',')),
           'process.crossOrigin': JSON.stringify(config.crossOrigin),
           'process.browser': JSON.stringify(!isServer)
         }

packages/next/client/index.js

@@ -21,6 +21,15 @@ if (!window.Promise) {
 
 const data = JSON.parse(document.getElementById('__NEXT_DATA__').textContent)
 window.__NEXT_DATA__ = data
+if (data && typeof data.passEnv === 'object') {
+  Object.keys(data.passEnv).forEach((key) => {
+    if (typeof global.process === 'undefined') {
+      global.process = {env: {}}
+    }
+
+    process.env[key] = data.passEnv[key]
+  })
+}
 
 const {
   props,