Read S3 file from AWS lambda NodeJS

var AWS = require('aws-sdk');
var s3 = new AWS.S3();

exports.handler = function(event, context, callback) {

    // Retrieve the bucket & key for the uploaded S3 object that
    // caused this Lambda function to be triggered
    // var src_bkt = event.Records[0].s3.bucket.name;
    // var src_key = event.Records[0].s3.object.key;
   
    var src_bkt = "app-proc-results";
            var src_key = "app.csv";
       

    // Retrieve the object
    s3.getObject({
        Bucket: src_bkt,
        Key: src_key
    }, function(err, data) {
        if (err) {
            console.log(err, err.stack);
            callback(err);
        } else {
            console.log("Raw text:\n" + data.Body.toString('ascii'));
            callback(null, null);
        }
    });
};

https://stackoverflow.com/questions/30651502/how-to-get-contents-of-a-text-file-from-aws-s3-using-a-lambda-function