feat: close #887 import masks

app/utils.ts

@@ -42,6 +42,26 @@ export function downloadAs(text: string, filename: string) {
   document.body.removeChild(element);
 }
 
+export function readFromFile() {
+  return new Promise<string>((res, rej) => {
+    const fileInput = document.createElement("input");
+    fileInput.type = "file";
+    fileInput.accept = "application/json";
+
+    fileInput.onchange = (event: any) => {
+      const file = event.target.files[0];
+      const fileReader = new FileReader();
+      fileReader.onload = (e: any) => {
+        res(e.target.result);
+      };
+      fileReader.onerror = (e) => rej(e);
+      fileReader.readAsText(file);
+    };
+
+    fileInput.click();
+  });
+}
+
 export function isIOS() {
   const userAgent = navigator.userAgent.toLowerCase();
   return /iphone|ipad|ipod/.test(userAgent);