nodejs AWS Lambda API function to return data that is different between 2 structured files

Please only make proposal if you have experience writing node functions for AWS Lambda. Write a nodejs AWS Lambda API function that will accept parameters that point to 2 different text files in an S3 bucket. One file in the S3 bucket with be the original file (let's call it file1). File1 will be a structured text file, like comma delimited .csv or tab delimited .txt. File2 will be a file just like file1 but some of the rows of data will be changed. A primary key will also be sent to the API function so the function can use the Primary Key rows to uniquely identify each row of data (the files will have a header row in first row that will be the names of the columns). Rows could have been updated, rows could have been removed, and new rows could have been added to file2. If the row has been updated, the primary key exists in both files but some of the data in the row has been changed. The row has been inserted if the primary key exists in file2, but not in file1. The row has been deleted if the primary key exists in file1 but not in file2. The function should compare the 2 files and return 3 files: 1. file_inserted - which will contain any rows of data in file2 that were added 2. file_updated - which will contain any updated rows of data from file2 3. file_deleted - which will contain any rows that were deleted from file2 So, API might be like: POST comparefiles with parameters: bucketname file1name file2name pkfields[ ]