1 files changed, 31 insertions, 0 deletions
diff --git a/src_js/file.ts b/src_js/file.ts
new file mode 100644
index 0000000..0466339
--- /dev/null
+++ b/src_js/file.ts
@@ -0,0 +1,31 @@
+
+
+export function load(ext: string): Promise<File | null> {
+    const el = document.createElement('input');
+    (el as any).style = 'display: none';
+    el.type = 'file';
+    el.accept = ext;
+    document.body.appendChild(el);
+
+    return new Promise<File | null>(resolve => {
+        const listener = (evt: Event) => {
+            const f = (evt.target as HTMLInputElement).files?.[0] ?? null;
+            document.body.removeChild(el);
+            resolve(f);
+        };
+        el.addEventListener('change', listener);
+        // TODO blur not fired on close???
+        el.addEventListener('blur', listener);
+        el.click();
+    });
+}
+
+
+export function save(f: File) {
+    const a = document.createElement('a');
+    a.download = f.name;
+    a.rel = 'noopener';
+    a.href = URL.createObjectURL(f);
+    setTimeout(() => { URL.revokeObjectURL(a.href); }, 20000);
+    setTimeout(() => { a.click(); }, 0);
+}