callbackErrorHandlingDynamoDB.js

let count = 1;
dynamoDB.batchWriteItem(params, processItemsCallback);
function processItemsCallback(err, data) {
  if (err) {
    console.log(JSON.stringify(err, null, 2));
  } else {
    console.log("Response Data: ", JSON.stringify(data));
    let itemsLost = data.UnprocessedItems;
    // Check if Object size is greater than 0 so we can process missed items if needed
    if (itemsLost.constructor === Object && Object.keys(itemsLost).length === 0) {
      console.log("Everything made it - hurray!");
    } else {
      console.log("Re-sending missed items");
      // Exponentially raise the backoff time
      count++;
      setTimeout(function(){
        let params = {};
        params.RequestItems = itemsLost;
        dynamoDB.batchWriteItem(params, processItemsCallback);
      }, 1000 * count);

    }
  }
}