feat: change JS to satisfy Dataflow JS engine (GoogleCloudPlatform#1808)

Co-authored-by: F. Hinkelmann <franziska.hinkelmann@gmail.com>

Author: sofisl

composer/composer_transform_csv_to_json.js

@@ -1,4 +1,5 @@
 /* eslint-disable func-style */
+/* eslint-disable no-var */
 // Copyright 2020 Google LLC
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
@@ -19,8 +20,8 @@ module.exports = function main(
  // [START composer_transform_csv_to_json]
 
  function transformCSVtoJSON(line) {
- const values = line.split(',');
- const properties = [
+ var values = line.split(',');
+ var properties = [
  'location',
  'average_temperature',
  'month',
@@ -30,13 +31,13 @@ module.exports = function main(
  ];
  const weatherInCity = {};
 
- for (let count = 0; count < values.length; count++) {
+ for (var count = 0; count < values.length; count++) {
  if (values[count] !== 'null') {
  weatherInCity[properties[count]] = values[count];
  }
  }
 
- const jsonString = JSON.stringify(weatherInCity);
+ var jsonString = JSON.stringify(weatherInCity);
  return jsonString;
  }