How to check if the string is base64 encoded when receiving data from node-imap

Question

There's a few answers about this on StackOverflow, but none of them work for me.

I have mixed data coming from Google mailbox import (some are in utf-8, some are in base64) into my Node.Js app and I need to check for every string if it's in base64 or not.

Does anyone have a solution that works?

Data example

0KHQvdCw0YfQsNC70LAg0YHQvtC30LTQsNC10YLRgdGPINGA0LXRiNC10YLQutCwINC/0YDQvtGB
0YLRgNCw0L3RgdGC0LLQsCDQstC+0L7QsdGA0LDQttC10L3QuNGPLiZuYnNwOzxkaXY+PGJyPjwv
ZGl2PjxkaXY+0JfQsNGC0LXQvCDQvdCwINC90LXQtSDQvdCw0L3QuNC30YvQstCw0LXRgtGB0Y8g
0LLRi9C80YvRgdC10LsuPC9kaXY+PGRpdj48

Code to get it github.com/mscdex/node-imap but I keep only the message text, ie

msg.on('body', function(stream, info) { 
  stream.on('data', function(chunk) {
    count += chunk.length;
    buffer += chunk.toString('utf8');
  }
}

Answer 1

The problem is that data I was receiving via node-imap module of Node.Js contained two different encoding parameters in the params:

attrs.struct[0].params.charset

would be set as utf-8 encoding for all messages

while

attrs.struct[0].encoding

for the messages that were in base64 encoding would be set as BASE64

So I passed on the both parameters in variables to the msg.once('end') , check if the attrs.struct[0].encoding is base64 and apply conversion for such strings from base64 to utf-8:

statement = new Buffer(email, 'base64').toString('utf8');

The rest get controlled through

statement = mimelib.decodeQuotedPrintable(email);