fix(Map): Unified settings. Second part: Import/Export

assets/js/hooks/Mapper/utils/loadTextFile.ts

@@ -0,0 +1,27 @@
+export function loadTextFile(): Promise<string> {
+  return new Promise((resolve, reject) => {
+    const input = document.createElement('input');
+    input.type = 'file';
+    input.accept = 'application/json,.json';
+
+    input.onchange = () => {
+      const file = input.files?.[0];
+      if (!file) {
+        reject(new Error('No file selected'));
+        return;
+      }
+
+      const reader = new FileReader();
+      reader.onload = () => {
+        resolve(reader.result as string);
+      };
+      reader.onerror = () => {
+        reject(reader.error);
+      };
+
+      reader.readAsText(file);
+    };
+
+    input.click();
+  });
+}