asyncMultiGet.js

function asyncMultiGet(keys) {
  return AsyncStorage.multiGet(keys)
    .then((err, data) => {
      if (! err) {
        return data.reduce(function (carry, val) {
          carry[val[0]] = val[1];
          return carry;
        }, {});
      }
      
      // TODO Handle errors
    });
}

// Usage
asyncMultiGet(['key1', 'key2'])
  .then((data) => {
    // {"key1": "value1", "key2": "value2"}
    console.log(data);
  });


// This becomes even easier if you use async/await:
let data = await asyncMultiGet(['key1', 'key2']);

// {"key1": "value1", "key2": "value2"}
console.log(data);