drop extra wrapping map and make $ shortcut more general

src/wasm/index.html

@@ -11,15 +11,18 @@
    />
    <script data-trunk src="./file-byte-reader.js"></script>
    <script>
-      let $ = (query) => document.querySelector(query);
+      let $ = (query, ele = document) => ele.querySelector(query);
 
       function fileLoaded(array) {
-         let hash = new Map(Object.entries(window.wasmBindings.previews(array)));
-         hash.forEach((images, key) => {
+         let wrapper = $('preview-wrapper');
+         wrapper.textContent = "";
+
+         let parser_images = window.wasmBindings.previews(array);
+         for (const [key, images] of Object.entries(parser_images)) {
             const container = document.createElement("preview-area");
             images.forEach(src => container.appendChild(new PreviewItem(src)));
-            $('preview-wrapper').appendChild(container);
-         })
+            wrapper.appendChild(container);
+         }
       }
 
       document.addEventListener("DOMContentLoaded", () => {
@@ -33,8 +36,8 @@
             super();
             const shadow = this.attachShadow({mode: "open"});
             const fragment = document.createRange().createContextualFragment('<h3></h3><img/>');
-            const h3 = fragment.querySelector('h3');
-            this.img = fragment.querySelector("img");
+            const h3 = $('h3', fragment);
+            this.img = $('img', fragment);
 
             this.img.onload = function () {
                h3.innerText = this.width;