feat: add “opt.origins” for inspecting before queue;

- 771 gz (+30 bytes)

src/index.mjs

@@ -48,6 +48,7 @@ function prefetcher(url) {
  * @param {Array} options.urls - Array of URLs to prefetch (override)
  * @param {Object} options.el - DOM element to prefetch in-viewport links of
  * @param {Boolean} options.priority - Attempt higher priority fetch (low or high)
+ * @param {Array} options.origins - Allowed origins to prefetch (empty allows all)
  * @param {Number} options.timeout - Timeout after which prefetching will occur
  * @param {function} options.timeoutFn - Custom timeout function
  */
@@ -61,6 +62,8 @@ export default function (options) {
 
   observer.priority = options.priority;
 
+  const allowed = options.origins || [];
+
   options.timeoutFn(() => {
     // If URLs are given, prefetch them.
     if (options.urls) {
@@ -69,7 +72,11 @@ export default function (options) {
       // If not, find all links and use IntersectionObserver.
       Array.from(options.el.querySelectorAll('a'), link => {
         observer.observe(link);
-        toPrefetch.add(link.href);
+        // If the anchor matches a permitted origin
+        // ~> An empty list means everything is allowed
+        if (!allowed.length || allowed.includes(link.hostname)) {
+          toPrefetch.add(link.href);
+        }
       });
     }
   }, {timeout: options.timeout});