retrieve a JSON element nodejs lambda aws - aws-lambda

Question

I got a lambda function which retrieves elements from dynamodb. When I tried to extract an individual Item or more from the JSON object which contains the elements from the database they are undefined, how can I return an individual element? for example 'date_booking'. The following is the code of the function.
Thanks in advance.
'use strict';
const AWS = require('aws-sdk');
const docClient = new AWS.DynamoDB.DocumentClient({region: 'us-west-2'});
function close(sessionAttributes, fulfillmentState, message) {
return {
sessionAttributes,
dialogAction: {
type: 'Close',
fulfillmentState,
message,
},
};
}
// --------------- Events -----------------------
function dispatch(intentRequest, callback) {
const sessionAttributes = intentRequest.sessionAttributes;
const slots = intentRequest.currentIntent.slots;
const phone = slots.PhoneNumber;
let params = {
TableName: 'bookings',
Key: {
"phone_number": phone
},
ProjectionExpression:"date_booking, time_booking"
};
docClient.get(params, function(err, data) {
if (err) {
callback(err, null);
} else {
callback(null,data);
console.log(data);
console.log(data.date_booking);
console.log(data.time_booking);
}
});
}
// --------------- Main handler -----------------------
exports.handler = (event, context, callback) => {
try {
dispatch(event,
(response) => {
callback(null, response);
});
} catch (err) {
callback(err);
}
};
The executions results are:
Function Logs:
START RequestId: 5536b82c-c538-11e8-ad44-474e44b2f858 Version: $LATEST
2018-10-01T05:10:38.653Z 5536b82c-c538-11e8-ad44-474e44b2f858 { Item:
{ date_booking: '2018-09-18', time_booking: '15:00' } }
2018-10-01T05:10:38.712Z 5536b82c-c538-11e8-ad44-474e44b2f858
undefined
2018-10-01T05:10:38.730Z 5536b82c-c538-11e8-ad44-474e44b2f858
undefined
END RequestId: 5536b82c-c538-11e8-ad44-474e44b2f858
REPORT RequestId: 5536b82c-c538-11e8-ad44-474e44b2f858 Duration: 1301.50 ms
Billed Duration: 1400 ms Memory Size: 128 MB Max Memory Used: 30 MB

Answer 1

Getting data from dynamoDB as in Item.
docClient.get(params, function(err, data) {
if (err) {
callback(err, null);
console.log(err)
} else {
console.log(data.Item.date_booking);
}
});

Answer 2

You can use the following.
const AWS = require('aws-sdk');
const docClient = new AWS.DynamoDB.DocumentClient({region: 'us-west-2'});
exports.handler = (event, context, callback) => {
var params = {
TableName: 'bookings',
Key:{
date_booking: event.params.path.date_booking
//date_booking is the item you want to retrieve
}
};
docClient.get(params, function(err, data) {
if (err) {
callback(err, null);
console.log(err)
} else {
callback(null, data);
console.log(data);
}
});
};