Promise not executing when wrapped in a function - node.js

Question

I am new to NodeJS and i am trying to post a message to AWS SNS from lambda. I took the code from AWS code samples and it is working fine in lambda.
But when i wrapped the same code in a function aand invoked from the main handler it is not working..
I tried returning and resolving the promise but nothing works.
// Load the AWS SDK for Node.js
var AWS = require('aws-sdk');
// Set region
exports.handler = async (event, context) => {
saveToSNS();
};
function saveToSNS() {
console.log("sdsdsd");
var AWS = require('aws-sdk');
var params = {
Message: 'MESSAGE_TEXT', /* required */
TopicArn: '<MY TOPIC>'
};
// Create promise and SNS service object
var publishTextPromise = new AWS.SNS({apiVersion: '2010-03-31'}).publish(params).promise();
// Handle promise's fulfilled/rejected states
return publishTextPromise.then(
function(data) {
console.log("sdsdsd");
console.log("Message ${params.Message} send sent to the topic ${params.TopicArn}");
console.log("MessageID is " + data.MessageId);
}).catch(
function(err) {
console.error(err, err.stack);
});
}

Answer 1

You need to place all code inside the handler as well. You can try like this:
exports.handler = async (event, context) => {
// Load the AWS SDK for Node.js
var AWS = require('aws-sdk');
// Set region
AWS.config.update({region: 'REGION'});
saveToSNS();
function saveToSNS() {
// Create publish parameters
var params = {
Message: 'MESSAGE_TEXT', /* required */
TopicArn: 'TOPIC_ARN'
};
// Create promise and SNS service object
var publishTextPromise = new AWS.SNS({apiVersion: '2010-03-31'}).publish(params).promise();
publishTextPromise.then(function(data) {
console.log("Message ${params.Message} send sent to the topic ${params.TopicArn}");
console.log("MessageID is " + data.MessageId);
}).catch(function(err) {
console.error(err, err.stack);
});
}
};

Answer 2

You can either use async/await like this:
// Load the AWS SDK for Node.js
var AWS = require('aws-sdk');
// Set region
exports.handler = async (event, context) => {
await saveToSNS();
};
async function saveToSNS() {
console.log("sdsdsd");
var AWS = require('aws-sdk');
var params = {
Message: 'MESSAGE_TEXT', /* required */
TopicArn: '<MY TOPIC>'
};
// Create promise and SNS service object
var publishTextPromise = new AWS.SNS({apiVersion: '2010-03-31'}).publish(params).promise();
// Handle promise's fulfilled/rejected states
return publishTextPromise.then(
function(data) {
console.log("sdsdsd");
console.log("Message ${params.Message} send sent to the topic ${params.TopicArn}");
console.log("MessageID is " + data.MessageId);
}).catch(
function(err) {
console.error(err, err.stack);
});
}
or add the return statement before calling saveToSNS() function, like this:
exports.handler = async (event, context) => {
return saveToSNS();
};