golf(breaking): use Boolean for priority option;

- is only low vs high
- 832 gz / 673 br

src/index.mjs

@@ -42,14 +42,14 @@ function prefetcher(url) {
  * @param {Object} options - Configuration options for quicklink
  * @param {Array} options.urls - Array of URLs to prefetch (override)
  * @param {Object} options.el - DOM element to prefetch in-viewport links of
- * @param {string} options.priority - Attempt to fetch with higher priority (low or high)
+ * @param {Boolean} options.priority - Attempt higher priority fetch (low or high)
  * @param {Number} options.timeout - Timeout after which prefetching will occur
  * @param {function} options.timeoutFn - Custom timeout function
  */
 export default function (options) {
   options = Object.assign({
-    priority: 'low',
     timeout: 2e3,
+    priority: false,
     timeoutFn: requestIdleCallback,
     el: document,
   }, options);

src/prefetch.mjs

@@ -113,11 +113,11 @@ const supportedPrefetchStrategy = support(`prefetch`)
 
 /**
  * Prefetch a given URL with an optional preferred fetch priority
- * @param {string} url - the URL to fetch
- * @param {string} priority - preferred fetch priority (`low` or `high`)
+ * @param {String} url - the URL to fetch
+ * @param {Boolean} isPriority - if is "high" priority
  * @return {Object} a Promise
  */
-async function prefetcher(url, priority) {
+async function prefetcher(url, isPriority) {
   if (preFetched[url]) {
     return;
   }
@@ -134,11 +134,7 @@ async function prefetcher(url, priority) {
   }
 
   try {
-    if (priority && priority === `high`) {
-      await highPriFetchStrategy(url);
-    } else {
-      await supportedPrefetchStrategy(url);
-    };
+    await (isPriority ? highPriFetchStrategy : supportedPrefetchStrategy)(url);
     preFetched[url] = true;
   } catch (e) {
     // Wanna do something?