Implement basic placeholder skeleton when loading

the post() function now uses await syntax rather than .then()

src/App.css

@@ -38,7 +38,8 @@ body {
   overflow: clip;
 }
 
-.GalleryItem > img, video {
+.GalleryItem > img,
+.GalleryItem > video {
   object-fit: contain;
   max-height: 80vh;
 }
@@ -62,7 +63,16 @@ body {
   background-color: #0056b3;
 }
 
+.PlaceholderItem > button,
 .ParentDirectoryItem > button {
 	background-color: #4D4F5D;
 }
 
+.PlaceholderItem > a {
+  height: 1em;
+}
+
+.PlaceholderItem > button {
+  height: calc(16px + 10px * 2);
+  width: 6em;
+}

src/App.tsx

@@ -1,4 +1,3 @@
-import React from 'react';
 import './App.css';
 
 import Gallery from './Gallery/index';

src/Gallery/index.tsx

@@ -1,24 +1,30 @@
 import React from 'react';
 import '../App.css';
+import placeholderPng from './placeholder.png';
 import { useState, useEffect } from 'react';
 
 function Gallery() {
-  const [data, setData] = useState('');
+  const [data, setData] = useState<galleryItemInfo[]>([]);
   const [category, setCategory] = useState('');
 
   useEffect(() => {
-    post(category, (json: string) => {
-      setData(json);
+    post(category, (data: galleryItemInfo[]) => {
+      setData(data);
     });
-  });
+  }, [category]);
+
+  const updateCategory = (category: string) => {
+    setData(getPlaceholderData);
+    setCategory(category);
+  };
 
   return (
     <div className="Gallery">
       <div className="Header">
-        {getContents(data, true, category, setCategory)}
+        {Contents(data, true, category, updateCategory)}
       </div>
       <div className="Contents">
-        {getContents(data, false, category, setCategory)}
+        {Contents(data, false, category, updateCategory)}
       </div>
     </div>
   );
@@ -28,32 +34,25 @@ interface galleryItemInfo {
   is_dir: boolean;
   url: string;
   thumbnail_url: string;
+
+  isPlaceholder: boolean;
 }
 
-function getContents(
-  data: string,
+function Contents(
+  data: galleryItemInfo[],
   getDir: boolean,
   category: string,
   setCategory: (category: string) => void
 ) {
-  if (data === '') return;
+  if (data === null) return;
 
-  let obj = null;
-  try {
-    obj = JSON.parse(data);
-  } catch (error: unknown) {
-    if (!(error instanceof SyntaxError)) {
-      throw new Error(error as unknown as undefined);
-    }
-    return data;
-  }
-
-  return obj
-    .sort((a: galleryItemInfo, b: galleryItemInfo) => {
+  return data
+    .sort((a: galleryItemInfo, b: galleryItemInfo): number => {
       if (a.is_dir && b.is_dir) return 0;
       if (a.is_dir && !b.is_dir) return -1;
       if (!a.is_dir && b.is_dir) return 1;
       if (!a.is_dir && !b.is_dir) return 0;
+      return 0;
     })
     .filter((item: galleryItemInfo) => {
       return getDir == item.is_dir;
@@ -65,6 +64,7 @@ function getContents(
         thumbnail_url:
           item.thumbnail_url === null ? item.url : item.thumbnail_url,
         onClick: () => {},
+        isPlaceholder: item.isPlaceholder,
       };
 
       if (item.is_dir) {
@@ -91,11 +91,13 @@ interface galleryItem {
   url: string;
   thumbnail_url: string;
   onClick: () => void;
+  isPlaceholder: boolean;
 }
 
-function ImageItem({ thumbnail_url, url }: galleryItem) {
+function ImageItem({ thumbnail_url, url, isPlaceholder }: galleryItem) {
+  const placeholderClass = isPlaceholder ? 'PlaceholderItem' : '';
   return (
-    <div className="GalleryItem">
+    <div className={`GalleryItem ${placeholderClass}`}>
       <a href={url} target="_blank">
         {getFileName(url)}
       </a>
@@ -117,16 +119,15 @@ function VideoItem({ url }: galleryItem) {
   );
 }
 
-function DirectoryItem({ url, onClick }: galleryItem) {
+function DirectoryItem({ url, onClick, isPlaceholder }: galleryItem) {
   let buttonText = getFileName(url);
   const isBackButton = buttonText === '..';
-  buttonText = isBackButton ? 'Back' : `Category: ${buttonText}`;
+  const placeholderClass = isPlaceholder ? 'PlaceholderItem' : '';
+  buttonText = isBackButton ? 'Back' : `${buttonText}`;
   const backButtonClass = isBackButton ? 'ParentDirectoryItem' : '';
   return (
-    <div className={`DirectoryItem ${backButtonClass}`}>
-      <button className="DirectoryItem" onClick={onClick}>
-        {buttonText}
-      </button>
+    <div className={`DirectoryItem ${backButtonClass} ${placeholderClass}`}>
+      <button onClick={onClick}>{buttonText}</button>
     </div>
   );
 }
@@ -135,33 +136,62 @@ function getFileName(string: string): string {
   return string.split('/').at(-1) as unknown as string;
 }
 
-function post(category: string, callback: (text: string) => void) {
-  fetch(
-    'http://localhost/photo-viewer-backend/php/get.php',
-    //'https://dundun.ddns.net/photo-viewer/photo-viewer-backend/php/get.php',
-    {
-      method: 'POST',
-      headers: {
-        'Content-Type': 'application/json',
-      },
-      body: JSON.stringify({
-        category: category,
-      }),
-    }
-  )
-    .then((response) => {
-      if (!response.ok) {
-        throw new Error('Network response was not ok');
+function getPlaceholderData(): galleryItemInfo[] {
+  const placeholderDir = (): galleryItemInfo => {
+    return {
+      is_dir: true,
+      url: '',
+      thumbnail_url: '',
+      isPlaceholder: true,
+    };
+  };
+  const placeholderImg = (): galleryItemInfo => {
+    return {
+      is_dir: false,
+      url: '',
+      thumbnail_url: `${placeholderPng}`,
+      isPlaceholder: true,
+    };
+  };
+
+  return [
+    placeholderDir(),
+    placeholderDir(),
+    placeholderImg(),
+    placeholderImg(),
+    placeholderImg(),
+  ];
+}
+async function post(
+  category: string,
+  setDataCallback: (data: galleryItemInfo[]) => void
+) {
+  try {
+    const response = await fetch(
+      //'http://localhost/photo-viewer-backend/php/get.php',
+      'https://dundun.ddns.net/photo-viewer/photo-viewer-backend/php/get.php',
+      {
+        method: 'POST',
+        headers: {
+          'Content-Type': 'application/json',
+        },
+        body: JSON.stringify({
+          category: category,
+        }),
       }
-      return response;
-    })
-    .then((response) => response.text())
-    .then((data) => {
-      callback(data as unknown as string);
-    })
-    .catch((error) => {
-      console.error('There was a problem with the fetch operation:', error);
-    });
+    );
+    setDataCallback(await response.json());
+  } catch (error) {
+    console.error('Error fetching data: ', error);
+    setDataCallback([
+      {
+        is_dir: false,
+        url: 'error_fetching',
+        thumbnail_url: '',
+        isPlaceholder: false,
+      },
+    ]);
+  }
 }
 
 export default Gallery;