fix: correctly handle format_auto,animated (#235)

Co-authored-by: Pooya Parsa <[email protected]>

Author: jameswragg

README.md

@@ -95,6 +95,10 @@ Change format to `webp` and keep other things same as source:
 
 `/f_webp/static/buffalo.png`
 
+Automatically convert to a preferred format (avif/webp/jpeg). Uses the browsers `accept` header to negotiate:
+
+`/f_auto/static/buffalo.png`
+
 Keep original format (`png`) and set width to `200`:
 
 `/w_200/static/buffalo.png`

src/server.ts

@@ -64,9 +64,12 @@ export function createIPXH3Handler(ipx: IPX) {
     const mFormat = modifiers.f || modifiers.format;
     if (mFormat === "auto") {
       const acceptHeader = getRequestHeader(event, "accept") || "";
+      const animated = modifiers.animated ?? modifiers.a;
       const autoFormat = autoDetectFormat(
         acceptHeader,
-        !!(modifiers.a || modifiers.animated),
+        // #234 "animated" param adds {animated: ''} to the modifiers
+        // TODO: fix modifiers to normalized to boolean
+        !!animated || animated === "",
       );
       delete modifiers.f;
       delete modifiers.format;