Await finished function about line-reader

[dlarr]

Hello, , I found a way to achieve what I needed:
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...
           
    });