test: add metadata collector attr test

Author: adriaandotcom

dist/latest/auto-events.js

@@ -1,4 +1,4 @@
-/* Simple Analytics - Privacy-first analytics (docs.simpleanalytics.com/script; 2025-05-30; bf05; v12) */
+/* Simple Analytics - Privacy-first analytics (docs.simpleanalytics.com/script; 2025-06-04; 2fe0; v12) */
 /* eslint-env browser */
 
 (function (
@@ -560,8 +560,7 @@
         sendData(append, undefinedVar, trueVar);
       } else {
         try {
-          nav.sendBeacon
-            .bind(nav)(fullApiUrl + "/append", stringify(append));
+          nav.sendBeacon.bind(nav)(fullApiUrl + "/append", stringify(append));
         } catch (e) {
           // Fallback for browsers throwing "Illegal invocation" when the URL is invalid
           sendData(append, undefinedVar, trueVar);

dist/latest/latest.dev.js

@@ -0,0 +1,33 @@
+const { expect } = require("chai");
+const { createDOM } = require("./helpers/dom");
+
+describe("metadata via data attribute", function () {
+  it("uses data-metadata-collector attribute", function (done) {
+    const dom = createDOM({
+      settings: { autoCollect: false },
+      beforeRun(vmContext) {
+        const { runInContext } = require("vm");
+        runInContext(
+          "window.collector = function(data){ return { fromAttr: true, path: data.path }; };" +
+            "Object.defineProperty(document, 'currentScript', {get: function(){ return { getAttribute: function(name){ return name === 'data-metadata-collector' ? 'collector' : null; } }; }});",
+          vmContext
+        );
+      },
+    });
+
+    dom.window.sa_pageview("/attr");
+
+    setTimeout(() => {
+      const req = dom.sent.find(
+        (r) => r.type === "image" && /path=%2Fattr/.test(r.url)
+      );
+      expect(req, "pageview request").to.exist;
+      const url = new URL(req.url);
+      const meta = JSON.parse(
+        decodeURIComponent(url.searchParams.get("metadata"))
+      );
+      expect(meta).to.include({ fromAttr: true });
+      done();
+    }, 10);
+  });
+});