AsyncStorage.multiMerge()

Merges existing values with input values, assuming they are stringified json. Returns a Promise object.

Not supported by all native implementations.

Example:

// first user, initial values
let UID234_object = {
 name: 'Chris',
 age: 30,
 traits: {hair: 'brown', eyes: 'brown'},
};

// first user, delta values
let UID234_delta = {
 age: 31,
 traits: {eyes: 'blue', shoe_size: 10},
};

// second user, initial values
let UID345_object = {
 name: 'Marge',
 age: 25,
 traits: {hair: 'blonde', eyes: 'blue'},
};

// second user, delta values
let UID345_delta = {
 age: 26,
 traits: {eyes: 'green', shoe_size: 6},
};

let multi_set_pairs   = [['UID234', JSON.stringify(UID234_object)], ['UID345', JSON.stringify(UID345_object)]]
let multi_merge_pairs = [['UID234', JSON.stringify(UID234_delta)], ['UID345', JSON.stringify(UID345_delta)]]

AsyncStorage.multiSet(multi_set_pairs, (err) => {
  AsyncStorage.multiMerge(multi_merge_pairs, (err) => {
    AsyncStorage.multiGet(['UID234','UID345'], (err, stores) => {
      stores.map( (result, i, store) => {
        let key = store[i][0];
        let val = store[i][1];
        console.log(key, val);
        // => UID234 {"name":"Chris","age":31,"traits":{"shoe_size":10,"hair":"brown","eyes":"blue"}}
        // => UID345 {"name":"Marge","age":26,"traits":{"shoe_size":6,"hair":"blonde","eyes":"green"}}
      });
    });
  });
});