Introduction to DynamoDB on NodeJS

dynamodb-intro.js

var AWS = require('aws-sdk');
AWS.config.update({
  endpoint: "http://localhost:8000",
  region: "us-west-2",
  accessKeyId: "myKeyId",
  secretAccessKey: "secretKey"
});
var dyn = new AWS.DynamoDB();
var docClient = new AWS.DynamoDB.DocumentClient();

dyn.listTables(function (err, data) {
  if (data.TableNames.indexOf('Entries') === -1) {
    var params = {
      TableName : "Entries",
      KeySchema: [
        { AttributeName: "userId", KeyType: "HASH" },  //Partition key
        { AttributeName: "id", KeyType: "RANGE"}  //Sort key
      ],
      AttributeDefinitions: [
        { AttributeName: "userId", AttributeType: "S" },
        { AttributeName: "id", AttributeType: "N" }
      ],
      ProvisionedThroughput: {
        ReadCapacityUnits: 10,
        WriteCapacityUnits: 10
      }
    };
    dyn.createTable(params, function(err, data) {
      if (err) {
        console.log("Unable to create table. Error JSON:", JSON.stringify(err, null, 2));
      }
    });
  } else {
    var reqParams = {
        TableName: "Entries",
        Key: {
            "userId":  'BEN',
            "id": 2
        }
    };
    docClient.get(reqParams, function(err, data) {
      if (err) {
        console.log("Unable to read item. Error JSON:", JSON.stringify(err, null, 2));
      } else {
        if (Object.keys(data).length === 0) {
          var docParams = {
              TableName: "Entries",
              Item: {
                  "userId":  'BEN',
                  "id": 2,
                  "title": 'Slurpie',
                  "calories": 300
              },
          };
          docClient.put(docParams, function(err, data) {
            if (err) {
              console.log("Unable to add item. Error JSON:", JSON.stringify(err, null, 2));
            }
          });
        } else {
          console.log("Item insertion succeeded:", JSON.stringify(data, null, 2));
        }
      }
    });

    var query = {
      TableName: 'Entries',
      KeyConditionExpression: "#id = :userId",
      ExpressionAttributeNames:{
          "#id": "userId"
      },
      ExpressionAttributeValues: {
          ":userId":'BEN'
      }
    };
    docClient.query(query, function(err, data) {
      if (err) {
        console.log('Unable to query data. Error JSON:', JSON.stringify(err, null, 2));
      } else {
        console.log('Gathered queried item:', JSON.stringify(data, null, 2));
      }
    });
  }
});