implement file receive request with image-thumbnail-preview, share-menu on click additional to download and multiple file support by zipping file(s) to prepare for sending; add status "waiting.." and "preparing..." to UX; lock pointer-input when peer-node busy; tidy-up paste-mode deactivation

public/scripts/util.js

@@ -0,0 +1,79 @@
+// Polyfill for Navigator.clipboard.writeText
+if (!navigator.clipboard) {
+    navigator.clipboard = {
+        writeText: text => {
+
+            // A <span> contains the text to copy
+            const span = document.createElement('span');
+            span.textContent = text;
+            span.style.whiteSpace = 'pre'; // Preserve consecutive spaces and newlines
+
+            // Paint the span outside the viewport
+            span.style.position = 'absolute';
+            span.style.left = '-9999px';
+            span.style.top = '-9999px';
+
+            const win = window;
+            const selection = win.getSelection();
+            win.document.body.appendChild(span);
+
+            const range = win.document.createRange();
+            selection.removeAllRanges();
+            range.selectNode(span);
+            selection.addRange(range);
+
+            let success = false;
+            try {
+                success = win.document.execCommand('copy');
+            } catch (err) {
+                return Promise.error();
+            }
+
+            selection.removeAllRanges();
+            span.remove();
+
+            return Promise.resolve();
+        }
+    }
+}
+
+const zipper = (() => {
+
+    let zipWriter;
+    return {
+        addFile(file, options) {
+            if (!zipWriter) {
+                zipWriter = new zip.ZipWriter(new zip.BlobWriter("application/zip"), { bufferedWrite: true, level: 0 });
+            }
+            return zipWriter.add(file.name, new zip.BlobReader(file), options);
+        },
+        async getBlobURL() {
+            if (zipWriter) {
+                const blobURL = URL.createObjectURL(await zipWriter.close());
+                zipWriter = null;
+                return blobURL;
+            } else {
+                throw new Error("Zip file closed");
+            }
+        },
+        specifyOnProgress(onprogressCallback) {
+            zipWriter.onprogress = onprogressCallback;
+        },
+        async getZipFile(filename = "archive.zip") {
+            if (zipWriter) {
+                const file = new File([await zipWriter.close()], filename, {type: "application/zip"});
+                zipWriter = null;
+                return file;
+            } else {
+                throw new Error("Zip file closed");
+            }
+        },
+        async getEntries(file, options) {
+            return await (new zip.ZipReader(new zip.BlobReader(file))).getEntries(options);
+        },
+        async getData(entry, options) {
+            return await entry.getData(new zip.BlobWriter(), options);
+        },
+    };
+
+})();