Trigger file upload with button

Signed-off-by: Thomas Citharel <tcit@tcit.fr>

js/src/utils/upload.ts

@@ -0,0 +1,36 @@
+/**
+ * Async function to upload a file
+ */
+export function listenFileUpload(): Promise<File> {
+  return new Promise((resolve, reject) => {
+    const inputElement = document.createElement('input');
+    inputElement.type = 'file';
+    inputElement.onchange = () => {
+      if (inputElement.files && inputElement.files.length > 0) {
+        resolve(inputElement.files[0]);
+      }
+    };
+
+    inputElement.onerror = reject;
+    inputElement.click();
+  });
+}
+
+/**
+ * Async function to upload a file
+ */
+export function listenFileUploads(): Promise<FileList> {
+  return new Promise((resolve, reject) => {
+    const inputElement = document.createElement('input');
+    inputElement.type = 'file';
+    inputElement.multiple = true;
+    inputElement.onchange = () => {
+      if (inputElement.files && inputElement.files.length > 0) {
+        resolve(inputElement.files);
+      }
+    };
+
+    inputElement.onerror = reject;
+    inputElement.click();
+  });
+}