fix: initialize with panel with defaultIndex when display: none (#903)

* fix: use defaultPanel when it equals nearestAnchor

* test: add test for defaultIndex

* test: fix test for initial panel when size is 0

* fix: remove autoInit at defaultIndex test

Author: malangfox

src/Flicking.ts

@@ -1739,7 +1739,7 @@ class Flicking extends Component<FlickingEvents> {
     if (!defaultPanel) return;
 
     const nearestAnchor = camera.findNearestAnchor(defaultPanel.position);
-    const initialPanel = (nearestAnchor && defaultPanel.index !== nearestAnchor.panel.index) ? nearestAnchor.panel : defaultPanel;
+    const initialPanel = (nearestAnchor && defaultPanel.position !== nearestAnchor.panel.position && defaultPanel.index !== nearestAnchor.panel.index) ? nearestAnchor.panel : defaultPanel;
     control.setActive(initialPanel, null, false);
 
     if (!nearestAnchor) {

test/unit/Flicking.spec.ts

@@ -72,7 +72,7 @@ describe("Flicking", () => {
       );
 
       expect(flicking.currentPanel).not.to.be.null;
-      expect(flicking.currentPanel).to.equal(flicking.camera.findNearestAnchor(0).panel);
+      expect(flicking.currentPanel).to.equal(flicking.panels[0]);
     });
 
     [15, 30, 50, 100].forEach((width) => {
@@ -205,6 +205,12 @@ describe("Flicking", () => {
 
         expect(flicking.index).to.equal(0);
       });
+
+      it("should initialized with panel which has index equal to defaultIndex when panels are not visible.", async () => {
+        const flicking = await createFlicking(El.DEFAULT_HORIZONTAL.setWidth(0), { defaultIndex: 1 });
+
+        expect(flicking.index).to.equal(1);
+      });
     });
 
     describe("horizontal", () => {