toString() failed

[dlarr]

Hello,

I am trying to use this library to read from a buffer line by line, below the code I use :

const es = require('event-stream');
const stream = require('stream');

let bufferStream = new stream.PassThrough();
bufferStream.end(myBuffer);

bufferStream
	.pipe(es.split())
	.pipe(es.mapSync(function(line){

			// pause the readstream
			bufferStream.pause();

			// DO SOME PROCESSING OF THIS LINE

			// resume the readstream, possibly from a callback
			bufferStream.resume();

		}).on('error', function(err){
			console.log('Error while reading file.' + err);
		}).on('end', function(){
			console.log('end event !');
		}).on('close', function(){
			console.log('close event !');
		})
	);

It seems awsome, but the problem is that I get an error - feels like a noob error :(

buffer.js:556
      if (encoding === 'utf8') return buf.utf8Slice(start, end);
                                          ^

Error: "toString()" failed
    at stringSlice (buffer.js:556:43)
    at Buffer.toString (buffer.js:629:10)
    at StringDecoder.utf8Text [as text] (string_decoder.js:201:16)
    at StringDecoder.write (string_decoder.js:85:46)
    at Stream.<anonymous> (...\node_modules\split\index.js:53:24)
    at Stream.stream.write (...\node_modules\through\index.js:26:11)
    at PassThrough.ondata (_stream_readable.js:628:20)
    at emitOne (events.js:115:13)
    at PassThrough.emit (events.js:210:7)
    at PassThrough.Readable.read (_stream_readable.js:464:10)
    at flow (_stream_readable.js:835:34)
    at resume_ (_stream_readable.js:817:3)
    at _combinedTickCallback (internal/process/next_tick.js:138:11)
    at process._tickCallback (internal/process/next_tick.js:180:9)

Do you know what's happening ?

Thank for the lib anyway !

Regards.

[dlarr]

Hello, it has nothing to do with your lib. Nevertheless, I found a way to get rid of this error :
Not using this lib anymore sorry :(

class Splitter extends Transform {
    constructor(options){
        super(options);
        this.splitSize = options.splitSize;
        this.buffer = Buffer.alloc(0);
        this.continueThis = true;
    }
    stopIt() {
        this.continueThis = false;
    }

    _transform(chunk, encoding, cb){

        this.buffer = Buffer.concat([this.buffer, chunk]);

        while ((this.buffer.length > this.splitSize || this.buffer.length === 1) && this.continueThis){
            try {
                let chunk = this.buffer.slice(0, this.splitSize);

                this.push(chunk);
                this.buffer = this.buffer.slice(this.splitSize);
                if (this.buffer[0] === 26){
                    console.log('EOF : ' + this.buffer[0]);
                }
            } catch (err) {
                console.log('ERR OCCURED => ', err);
                break;
            }
        }
        console.log('WHILE FINISHED');
        cb();
    }
}

The to read your stuff simply do

let bufferStream = new stream.PassThrough();
bufferStream.end(hugeBuffer);
let splitter = new Splitter({splitSize : 170}); // In my case I have 170 length lines, so I want to process them line by line
let lineNr = 0;
bufferStream
      .pipe(splitter)
      .on('data', async function(line){

          line = line.toString().trim();

          splitter.pause(); // pause stream so you can perform long time processing with await
          lineNr++;
          
         if (lineNr === 1){
              // DO stuff with 1st line
              
         } else {
              splitter.stopIt(); // Break the stream and stop reading so we just read 1st line
         }

         splitter.resume() // resumestream so you can process next chunk
    }).on('error', function(err){
            console.log('Error while reading file.' + err);
            // whatever
     }).on('end', async function(){
           console.log('end event');

           // Stream has ended, do whatever...
           
    });