unmarshalled.js

import AWS from 'aws-sdk';

const params = {
  string: {S: 'foo'},
  list: {L: [{S: 'fizz'}, {S: 'buzz'}, {S: 'pop'}]},
  map: {
    M: {
      nestedMap: {
        M: {
          key: {S: 'value'}
        }
      }
    }
  },
  number: {N: '123'},
  nullValue: {NULL: true},
  boolValue: {BOOL: true}
};

const { unmarshalled } = AWS.DynamoDB.Converter;

const convertedParams = unmarshalled(params);