From 7b6e3d61c9dae68a45758323cfd952d2b8098800 Mon Sep 17 00:00:00 2001
From: soulgalore <peter@soulgalore.com>
Date: Wed, 21 Aug 2024 07:55:31 +0200
Subject: [PATCH] docs: example for lighthouse using headers

---
 docs/documentation/sitespeed.io/lighthouse/index.md | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/docs/documentation/sitespeed.io/lighthouse/index.md b/docs/documentation/sitespeed.io/lighthouse/index.md
index 0512d62b0..8e49b2139 100644
--- a/docs/documentation/sitespeed.io/lighthouse/index.md
+++ b/docs/documentation/sitespeed.io/lighthouse/index.md
@@ -53,10 +53,17 @@ module.exports = {
 };
 ```
 
-You can also add Lighthouse flags by a JSON file ```--lighthouse.flags flag.json```.
+You can also add Lighthouse flags by a JSON file ```--lighthouse.flags flag.json```. If you pass on command like flags that contains hyphens, they are removed and converted internally in Lighthouse, so for example to get the command line flag `--extra-headers` to work, the JSON should be like this:
+
+```JSON
+{
+    "extraHeaders": { "key": "value"} 
+}
+```
 
 Read all about configuring Lighthouse at [https://github.com/GoogleChrome/lighthouse/blob/master/docs/configuration.md](https://github.com/GoogleChrome/lighthouse/blob/master/docs/configuration.md).
 
+
 ## Disable GPSI
 If you only want to run Lighthouse and not GPSI you can disable it with `----plugins.remove @sitespeed.io/plugin-gpsi`.