react native error - Failed to execute 'importScripts' on 'WorkerGlobalScope'

var formBody = [];
for (var property in details) {
  var encodedKey = encodeURIComponent(property);
  var encodedValue = encodeURIComponent(details[property]);
  formBody.push(encodedKey + "=" + encodedValue);
}
formBody = formBody.join("&");

fetch('http://example.com/test.php?d=data', {
  method: 'POST',
  headers: {
   'Accept': 'application/json',
   'Content-Type': 'application/x-www-form-urlencoded'
 },
 body: formBody
 }).  
 .then((response) => response.json())
        .then((responseData) => {
            console.log("Response:",responseData);
         }).catch((error) => {
                Alert.alert('problem while adding data');
            })
        .done();