MissingRequiredParameter: Missing required key 'Message' in params - amazon-web-services

Question

I'm trying to invoke a code in AWS Lambda. This Lambda code has been configured with my IOT button. On running this code, I don't see any errors. Also,I don't really see the required push notification on my mobile device.
I can see this message in my console : MissingRequiredParameter: Missing required key 'Message' in params
This is my code:
'use strict';
console.log('Loading function');
var AWS = require('aws-sdk');
var sns = new AWS.SNS();
AWS.config.region = 'xxxxx';
const TopicArn = 'xxxxxxxxxxxxxxxxxxxxxxxxxx'
exports.handler = function(event, context) {
console.log("\n\nLoading handler\n\n");
console.log('Received event:', event);
const sin =
{
"default": "Start",
"APNS_SANDBOX":"{\"aps\":{\"alert\":\"Start\"}}",
"GCM": "{ \"notification\": { \"text\": \"Start\" } }"
} // for single click
const doub = {
"default": "Stop",
"APNS_SANDBOX":"{\"aps\":{\"alert\":\"Stop\"}}",
"GCM": "{ \"notification\": { \"text\": \"Stop\" } }"
} // for double click
const lon = {
"default": "SOS",
"APNS_SANDBOX":"{\"aps\":{\"alert\":\"SOS\"}}",
"GCM": "{ \"notification\": { \"text\": \"SOS\" } }"
} // for long click
var singleClick = sin[Math.floor(Math.random()*sin.length)];
var doubleClick = doub[Math.floor(Math.random()*doub.length)];
var longClick = lon[Math.floor(Math.random()*lon.length)];
var randomMessage = singleClick;
if(event.clickType == "DOUBLE")
{
randomMessage = doubleClick;
}
if(event.clickType == "LONG")
{
randomMessage = longClick;
}
sns.publish ({
Message: randomMessage,
TopicArn: TopicArn
},
function(err, data) {
if (err) {
console.log(err.stack);
return;
}
console.log('push sent');
console.log(data);
context.done(null, 'Function Finished!');
});
}
Can someone help me debug this error?

Answer 1

I found the answer. I had to define my variable too as a string using stringify() command or else JSON formatted message cannot be sent.