From e7c1edadc8c7ba0ecd5bde977cffc9813cb1b237 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?P=C3=A9ter=20J=C3=B3zsa?= <peter.jozsa@icloud.com>
Date: Thu, 24 Sep 2020 10:37:26 +0200
Subject: [PATCH] Add support for dynamic assetPrefix via next runtime
 configuration utils.

---
 index.js | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/index.js b/index.js
index 999e0ab..652e3d5 100644
--- a/index.js
+++ b/index.js
@@ -1,5 +1,8 @@
 module.exports = (nextConfig = {}) => {
   return Object.assign({}, nextConfig, {
+    publicRuntimeConfig: Object.assign({}, nextConfig.publicRuntimeConfig, {
+      nextImagesAssetPrefix: nextConfig.assetPrefix
+    }),
     webpack(config, options) {
       const { isServer } = options;
       nextConfig = Object.assign({
@@ -28,6 +31,13 @@ module.exports = (nextConfig = {}) => {
               fallback: require.resolve("file-loader"),
               publicPath: `${nextConfig.assetPrefix || nextConfig.basePath}/_next/static/images/`,
               outputPath: `${isServer ? "../" : ""}static/images/`,
+              postTransformPublicPath: (p) => {
+                if (!nextConfig.assetPrefix) {
+                  return `(require("next/config").default().publicRuntimeConfig.nextImagesAssetPrefix || '') + ${p}`
+                }
+                // no need to dynamically prepend assetPrefix to p since it was defined in transpilation-time
+                return p
+              },
               name: "[name]-[hash].[ext]",
               esModule: nextConfig.esModule || false
             }