I have a Node.js AWS Lambda function and I am trying to read records from a CSV file in S3 and print its contents.

Below is my code to achieve the same however I am getting Null as output.

Code:

const AWS = require('aws-sdk');
const s3 = new AWS.S3();
const csv = require('csv-parser');
const bucket = 'awslambdabuckets';
const objectkey = 'record.csv';
const params = { Bucket: bucket, Key: objectkey };
const results = [];

exports.handler = async function (event, ctx, callback) {
    try {
        const file = s3.getObject(params).createReadStream();

        file
            .pipe(csv())
            .on('data', function (data) {
                results.push;
            })
            .on('end', () => {
                console.log(results);
                callback(null, results);
            });
    } catch (err) {
        console.log(err);
        callback(Error(err));
    }

};

Output:

Can someone help me point out what's the problem and how to fix it.

CodePudding user response：

You are not pushing the data to the result, see and make changes as below

exports.handler = async function (event, ctx, callback) {
  try {
      const file = s3.getObject(params).createReadStream();

      file
          .pipe(csv())
          .on('data', function (data) {
              results.push(data);
          })
          .on('end', () => {
              console.log(results);
              callback(null, results);
          });
  } catch (err) {
      console.log(err);
      callback(Error(err));
  }
};

CodePudding user response：

You are not pushing data to the array:

const AWS = require('aws-sdk');
const s3 = new AWS.S3();
const csv = require('csv-parser');
const bucket = 'awslambdabuckets';
const objectkey = 'record.csv';
const params = { Bucket: bucket, Key: objectkey };
const results = [];

exports.handler = function (event, ctx, callback) {
    try {
        const file = s3.getObject(params).createReadStream();

        file
            .pipe(csv())
            .on('data', function (data) {
                results.push(data); // --> here
            })
            .on('end', () => {
                console.log(results);
                callback(null, results);
            });
    } catch (err) {
        console.log(err);
        callback(Error(err));
    }

};