chore: refactor

Author: farfromrefug

src/core-tabs/tab-navigation/index-common.ts

@@ -1,10 +1,11 @@
 import { cssProperty } from '@nativescript-community/ui-material-core';
 // Types
-import { Color, CoreTypes, Property, booleanConverter } from '@nativescript/core';
+import { Color, CoreTypes, Frame, Property, booleanConverter } from '@nativescript/core';
 import { TabNavigationBase as TabNavigationBaseBase } from '../tab-navigation-base';
 
 import { TabNavigation as TabsDefinition } from '.';
 import { TabStripItem } from '../tab-strip-item';
+import { TabContentItem } from '../tab-content-item';
 
 export namespace knownCollections {
     export const items = 'items';
@@ -41,6 +42,42 @@ export class TabNavigationBase extends TabNavigationBaseBase implements TabsDefi
     public getTabBarItemTextTransform(tabStripItem: TabStripItem): CoreTypes.TextTransformType {
         return this.getItemLabelTextTransform(tabStripItem);
     }
+
+    public _loadUnloadTabItems(newIndex: number) {
+        const items = this.items;
+        if (!items) {
+            return;
+        }
+
+        const offsideItems = this.offscreenTabLimit;
+
+        const toLoad: TabContentItem[] = [];
+        const toUnload: TabContentItem[] = [];
+        for (let index = 0; index < items.length; index++) {
+            const item = items[index];
+            if (item) {
+                if (Math.abs(index - newIndex) <= offsideItems) {
+                    toLoad.push(item);
+                } else {
+                    toUnload.push(item);
+                }
+            }
+        }
+
+        if (this.unloadOnTabChange) {
+            toUnload.forEach((item) => item.unloadView(item.content));
+        }
+
+        const newItem = items[newIndex];
+        const selectedView = newItem && newItem.content;
+        if (selectedView instanceof Frame) {
+            selectedView._pushInFrameStackRecursive();
+        }
+
+        if (this.isLoaded) {
+            toLoad.forEach((item) => item.loadView(item.content));
+        }
+    }
 }
 
 export const swipeEnabledProperty = new Property<TabNavigationBase, boolean>({

src/core-tabs/tab-navigation/index.android.ts

@@ -385,49 +385,6 @@ export abstract class TabNavigation<T extends android.view.ViewGroup = any> exte
         super.disposeNativeView();
     }
 
-    public _loadUnloadTabItems(newIndex: number) {
-        const items = this.items;
-        if (!items) {
-            return;
-        }
-
-        const lastIndex = items.length - 1;
-        const offsideItems = this.offscreenTabLimit;
-
-        const toUnload = [];
-        const toLoad = [];
-
-        iterateIndexRange(newIndex, offsideItems, lastIndex, (i) => toLoad.push(i));
-
-        if (this.unloadOnTabChange) {
-            items.forEach((item, i) => {
-                const indexOfI = toLoad.indexOf(i);
-                if (indexOfI < 0) {
-                    toUnload.push(i);
-                }
-                toUnload.forEach((index) => {
-                    const item = items[index];
-                    if (items[index]) {
-                        item.unloadView(item.content);
-                    }
-                });
-            });
-        }
-
-        const newItem = items[newIndex];
-        const selectedView = newItem && newItem.content;
-        if (selectedView instanceof Frame) {
-            selectedView._pushInFrameStackRecursive();
-        }
-
-        toLoad.forEach((index) => {
-            const item = items[index];
-            if (this.isLoaded && items[index]) {
-                item.loadView(item.content);
-            }
-        });
-    }
-
     public onLoaded(): void {
         super.onLoaded();
 

src/core-tabs/tab-navigation/index.ios.ts

@@ -385,14 +385,15 @@ export abstract class TabNavigation<
 
         const tabStripItems = this.tabStrip && this.tabStrip.items;
         if (tabStripItems) {
-            if (tabStripItems[newIndex]) {
-                tabStripItems[newIndex]._emit(TabStripItem.selectEvent);
-                this.updateItemColors(tabStripItems[newIndex]);
+            const newItem = tabStripItems[newIndex];
+            if (newItem) {
+                newItem._emit(TabStripItem.selectEvent);
+                this.updateItemColors(newItem);
             }
-
-            if (tabStripItems[oldIndex]) {
-                tabStripItems[oldIndex]._emit(TabStripItem.unselectEvent);
-                this.updateItemColors(tabStripItems[oldIndex]);
+            const oldItem = tabStripItems[oldIndex];
+            if (oldItem) {
+                oldItem._emit(TabStripItem.unselectEvent);
+                this.updateItemColors(oldItem);
             }
         }
 
@@ -401,48 +402,6 @@ export abstract class TabNavigation<
         super.onSelectedIndexChanged(oldIndex, newIndex);
     }
 
-    public _loadUnloadTabItems(newIndex: number) {
-        const items = this.items;
-        if (!items) {
-            return;
-        }
-
-        const lastIndex = items.length - 1;
-        const offsideItems = this.offscreenTabLimit;
-
-        const toUnload = [];
-        const toLoad = [];
-
-        iterateIndexRange(newIndex, offsideItems, lastIndex, (i) => toLoad.push(i));
-        if (this.unloadOnTabChange) {
-            items.forEach((item, i) => {
-                const indexOfI = toLoad.indexOf(i);
-                if (indexOfI < 0) {
-                    toUnload.push(i);
-                }
-            });
-
-            toUnload.forEach((index) => {
-                const item = items[index];
-                if (items[index]) {
-                    item.unloadView(item.content);
-                }
-            });
-        }
-        const newItem = items[newIndex];
-        const selectedView = newItem && newItem.content;
-        if (selectedView instanceof Frame) {
-            selectedView._pushInFrameStackRecursive();
-        }
-
-        toLoad.forEach((index) => {
-            const item = items[index];
-            if (this.isLoaded && items[index]) {
-                item.loadView(item.content);
-            }
-        });
-    }
-
     public onMeasure(widthMeasureSpec: number, heightMeasureSpec: number): void {
         const width = Utils.layout.getMeasureSpecSize(widthMeasureSpec);
         const widthMode = Utils.layout.getMeasureSpecMode(widthMeasureSpec);