node stream not finish but emit end

I am reading this and wrote my codes based on examples.

My codes:

const through = require('through2'); const bluebird = require('bluebird');

function streamToPromise(stream) {
  return new Promise(function(resolve, reject) {
    stream.resume();
    stream.on("end", resolve);
    stream.on("error", reject);
  });
};

module.exports = {
  up: function up() {
    console.log('startstream');
    // Doc is sequelize Model
    const stream = Doc.createReadStream({
      include: [
        {
          repository: AssociatedRepo,
          as: 'on',
          required: false,
        },
      ],
    });

    stream.pipe(through({ objectMode: true }, (doc, enc, cb) => {
      console.log('docid', doc.id);
      return doc.destroy()
        .then(() => cb());
    }));
    return streamToPromise(stream).then((data) => {
      console.log('xxxxxxxxxx', data);
      return null;
    });
  },
};

I tried to use the above program to read and delete about 400 records. but from log, I found that the stream promise (streamToPromise(stream)) being resolved but still several records remaining. From log, I got:

xxxxxxxxxx undefined
docid 89934915596

How to fix this? Thanks

You'll need to wait for the end of the destination stream of the pipe, currently you are only waiting for the input stream. Use

const res = stream.pipe(through({objectMode: true}, …));
return streamToPromise(res);