Example Lambda that takes an event with a message and a message attribute and injects it into an ARN

aws-sns-message-push.js

/**
 * This is an example body that you would pass in through the test function
 *  {
 *    "snsMessage": "This is a test body that will come through",
 *    "messageAttributes": {
 *      "insurance_type": {
 *        "DataType": "String",
 *        "StringValue": "car"
 *      }
 *    }
 *  }
 */

console.log('Loading function');

var AWS = require('aws-sdk');
AWS.config.region = 'ap-southeast-2';

exports.handler = async function(event) {  

  async function publishMessage() {
    var params = {
      MessageAttributes: event.messageAttributes,
      Message: event.snsMessage, /* required */
      TopicArn: 'snsTopicArn'
    };
    
    // Create promise and SNS service object
    return new AWS.SNS({apiVersion: '2010-03-31'}).publish(params).promise()
      .then(() => {
        const response = {
          statusCode: 200,
          body: JSON.stringify('Publish Successful'),
        };
        return response;
      })
      .catch((err) => {
        console.error(err, err.stack);
        const response = {
          statusCode: 400,
          body: JSON.stringify('Publish Unsuccessful'),
        };
        return response;
      });
  };

  const eventResponse = await publishMessage()
  return eventResponse;
};