js代码优化

@@ -7,7 +7,10 @@
     Swiper = require('yoho.iswiper'),
     lazyLoad = require('yoho.lazyload');
 
-var goodsSwiper;
+var goodsSwiper,
+    $discountFolder = $('.goods-discount .discount-folder'),
+    $discountArrow = $('.goodsDiscount .first-item span');
+
 
 require('./desc');
 require('./comments-consults');
@@ -29,18 +32,18 @@ goodsSwiper = new Swiper('.banner-swiper', {
 
 //初始化goods-discount
 if (0 === $('.goods-discount .discount-folder').children().length) {
-    $('.goods-discount .discount-folder').css('display', 'none');
-    $('.goods-discount .first-item span').html('');
+    $discountFolder.css('display', 'none');
+    $discountArrow.html('');
 }
 
 //goods-discount下拉按钮点击事件
 $('.goodsDiscount .dropdown').on('click', function() {
-    if ($('.goodsDiscount .discount-folder').is(':hidden')) {
-        $('.goodsDiscount .first-item span').removeClass('icon-down').addClass('icon-up').html('');
-        $('.goodsDiscount .discount-folder').slideDown();
+    if ($discountFolder.is(':hidden')) {
+        $discountArrow.removeClass('icon-down').addClass('icon-up').html('');
+        $discountFolder.slideDown();
     } else {
-        $('.goodsDiscount .first-item span').removeClass('icon-up').addClass('icon-down').html('');
-        $('.goodsDiscount .discount-folder').slideUp();
+        $discountArrow.removeClass('icon-up').addClass('icon-down').html('');
+        $discountFolder.slideUp();
     }
 });
 require('./like');
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