fix(infiniteGrid): add defense code when the user forces the scroll (n…

…aver#474) * fix(infiniteGrid): add defense code when the user forces the scroll close naver#455 * skip: add test code
yoooom · Mar 10, 2017 · 9bbb159 · 9bbb159
1 parent f74fa1d
commit 9bbb159
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diff --git a/src/infiniteGrid.js b/src/infiniteGrid.js
@@ -59,6 +59,7 @@ eg.module("infiniteGrid", ["jQuery", eg, window, document], function($, ns, glob
 		"append": "append",
 		"prepend": "prepend"
 	};
+	var RETRY = 3;
 	ns.InfiniteGrid = ns.Class.extend(ns.Component, {
 		_events: function() {
 			return EVENTS;
@@ -450,6 +451,7 @@ eg.module("infiniteGrid", ["jQuery", eg, window, document], function($, ns, glob
 			addItems = addItems || [];
 
 			this.el.style.height = this._getContainerSize().height + "px";
+			this._doubleCheckCount = RETRY;
 
 			// refresh element
 			this._topElement = this.getTopElement();
@@ -486,6 +488,22 @@ eg.module("infiniteGrid", ["jQuery", eg, window, document], function($, ns, glob
 				distance: distance,
 				croppedCount: options.removedCount
 			});
+
+			// doublecheck!!! (workaround)
+			if (!options.isAppend) {
+				if (this._getScrollTop() === 0) {
+					var self = this;
+					clearInterval(this._doubleCheckTimer);
+					this._doubleCheckTimer = setInterval(function() {
+						if (self._getScrollTop() === 0) {
+							self.trigger(self._prefix + EVENTS.prepend, {
+								scrollTop: 0
+							});
+							(--self._doubleCheckCount <= 0) && clearInterval(self._doubleCheckTimer);
+						}
+					}, 500);
+				}
+			}
 		},
 
 		// $elements => $([HTMLElement, HTMLElement, ...])
@@ -641,6 +659,8 @@ eg.module("infiniteGrid", ["jQuery", eg, window, document], function($, ns, glob
 			this._prevScrollTop = 0;
 			this._equalItemSize = 0;
 			this._resizeTimeout = null;
+			this._doubleCheckTimer = null;
+			this._doubleCheckCount = RETRY;
 			this._resetCols(this._appendCols.length || 0);
 			this.items = [];
 		},

diff --git a/test/unit/js/infiniteGrid.test.js b/test/unit/js/infiniteGrid.test.js
@@ -399,6 +399,32 @@ QUnit.test("check item/element order and check removed parts", function(assert)
 	this.inst.append(getContent("append",30));
 });
 
+QUnit.test("check a prepend workaround code (doublecheck)", function(assert) {
+	// Given
+	// When
+	var done = assert.async();
+	var prependCount = 0;
+	this.inst.on({
+		"prepend": function(e) {
+			prependCount++
+		},
+		"layoutComplete": function(e) {
+			assert.equal(e.isAppend, false, "prepend type");
+			$(window).scrollTop(0);
+		}
+	});
+
+	// When
+	this.inst.prepend(getContent("prepend", 200));
+
+	setTimeout(function() {
+		// Then
+		assert.equal(prependCount, 3);
+		done();
+	}, 2000);
+});
+
+
 QUnit.module("infiniteGrid unit method Test", {
 	beforeEach : function() {
 		this.inst = null;